Didn't Think This Through

File:Mario Cunning Plan.jpg

Mr. Krabs: Plankton! You knew I would never distrust a dollar! Plankton: That's right, Krabs! Now hand over the Krabby Patty secret formula! [Beat Mr. Krabs: Or what? Plankton: I don't know. I never thought I'd get this far. Mr. Krabs: Well then, allow me to suggest your next move. [Mr. Krabs flushes Plankton down the toilet] —SpongeBob SquarePants

A situational trope. One character will develop a plan designed to solve a certain problem they're encountering. However, due to their failure to plan ahead, there is a massive gaping flaw in their plan that they, and also perhaps the audience, missed. As a result, they are now in a situation where, rather than winning, they are stuck with either a stalemate or an outright loss. As indicated by the page quote, this may occur because the character never thought that their plan would actually progress as far as it did in the first place.

A more comedic, simple version of Didn't See That Coming. If the person pointing this out is sufficiently annoyed, this can lead to What Were You Thinking?.

Examples of Didn't Think This Through include:

Anime and Manga

• At points in both the first and second seasons of Strike Witches, Minna pulls a gun on Mio in order to try to stop her from getting herself killed in battle. Mio is quite aware of the flaw in this bluff, and it doesn't work either time.
• Vegeta during the Saiyan battle in Dragon Ball after Gohan turned into a Oozaru. Escaping being crushed multiple times, he did seem proud of himself for a moment after cutting off the boy's tail, thus shrinking him to normal size. Given that, while Vegeta has taken a considerable beating fighting the various heroes, Gohan was the last one strong enough to present any kind of threat to him, it seems that he's won. Then comes the brief realization that Gohan is still semi-gigantic, not maintaining his place in the air and now falling towards him while semi-gigantic. All of this happens in about a second, leaving Vegeta no time to dodge. Not long after a crushed Vegeta is sitting in a crater, struggling to crawl to his ship.
• One Piece has the "Fake Straw Hat Pirates" based in Sabaody Archipelago after the time-skip. Since Monkey D. Luffy has attained even more infamy than ever before due to his part in the War at the Summit, One guy going by the name "Three Tongued" Demalo Black got the bright idea of posing as him and setting up a crew to pose as the Straw Hat Pirates, usually getting his way by relying on Luffy's fame to threaten people and recruit fearsome pirates into his crew. Unfortunately, round out the time they were recruiting the real Straw Hats came back, and it got steadily worse when they try to recruit a pair of Ax Crazy pirate captains who intend to kill the Straw Hats for more fame, and the Marines show up with Pacifistas, with a Marine Captain personally knocking out Demalo Black with his axe for trying to talk smack to him, while pretending to be Luffy.
• Almost happens in Mahou Sensei Negima. The cast are discussing ways to retrieve Asuna and the Great Grandmaster Key from the Big Bads, and get the idea to use Natsumi's artifact (which makes the enemy completely unable to sense your presence) to get close for an ambush. Unfortunately The Anti-Magic field coming from Asuna would make that plan useless. They almost go with the plan until Ako realizes the flaw. Cue Yue coming up with a workable solution, and a Crowning Moment of Awesome for everyone involved.

Comic Books

• In the climax of Northwest Passage, Montclave reveals critical information to Simon in the hopes of permanently turning him against his father, Charles Lord. The information is that Simon's parentage is a Luke, I Might Be Your Father situation, since Montglave raped Simon's mother at the time of conception. Unsurprisingly, Simon takes a rather dim view of this knowledge and promptly blows Montglave's brains out.
• Batman villain Warren "Great White Shark" White successfully pled insanity to escape embezzlement charges. He was sent to Arkham and wound up at the mercy of Gotham's worst psychopaths. Oops.

Film

• In Monty Python and The Holy Grail, when King Arthur's knights attempt to copy the Trojan Horse ploy with a giant wooden rabbit, none of them remember that they're supposed to get inside the rabbit until it's been taken into the castle.
  • Of course, given the French knights' predilection for catapulting just about everything they can find, actually getting into the rabbit would have been even worse.
  • This would also fit under Explain, Explain, Oh Crap.
• Lampshaded in Three Amigos. Dusty Bottoms has found Carmen in her place of imprisonment.

Dusty: We have a plan. Carmen: What is it? Dusty: First, we break into El Guapo's fortress. Carmen: And that you've done. Now what? Dusty: Well, we really didn't expect the first part of the plan to work, so we have no further plan. Sometimes you can overplan these things.

• Hermione says this very thing to Harry in the Prisoner of Azkaban movie, when she saves their past selves from the werewolf...by luring it over to their current selves.
• In Aladdin, Jafar is defeated when Aladdin tricks him into wishing to become an all-powerful genie. Jafar either forgot or was not aware that genies in this setting are bound to a magic lamp and obliged to grant wishes by nature.

Genie: It's all part and parcel of the whole Genie gig. PHENOMENAL COSMIC POWER! ...Itty-bitty living space.

• Gil's plan to escape to the sea in Finding Nemo which succeeds past the audience's expectations only to run into a snag at the end.
• A Strange Minds Think Alike style gag in Meet the Robinsons often said to Bowler Hat Guy. When a CEO, a frog and a tyrannosaurus rex think your evil plans need work, you aren't doing that well.

"It's just, I have this big head, and little arms. I'm just not sure how well this plan was thought through!"

• The Dark Knight Saga

Lucius Fox: Let me get this straight. You think that your client, one of the wealthiest, most influential men on the planet, is secretly a vigilante who spends his nights beating criminals to a pulp with his bare hands. And your plan is to blackmail this person? ...Good luck. Beat ...Keep that...

• The last line on Cloudy with a Chance of Meatballs, spoken by the Mayor, who is adrift at sea after eating the food boat he was escaping in.
  • In the DVD Commentary, the writers/directors lament that no one got the joke that this line was said immediately before the "Written and Directed by" credit showed up.
• In Its a Boy Girl Thing Woody (in Nell's body) decides to get her a reputation for being easy. So he decides to have her sleep with this really sleazy guy. The Didn't Think This Through example occurs just before the deed is to be done when Woody realises that he is actually going to be the one to experience the drunken sex with a guy. Also counts as an Oh Crap moment.
• This is Dallas's Fatal Flaw in Alien, when he's under pressure, he decides to act on impulse. So when there's an alien onboard that's planning to kill everyone, he decides he'll deal with it himself. He'll whip out a flamethrower and scare it into the airlock, where he'll launch into the space. However, he never bothers to check to see whether the alien is afraid of his flamethrower. And he decides to go after it alone, in a dark, cramped, passageway. Inevitably, the Xenomorph decides to take advantage of the situation and kills him.
• Done hilariously in Mystery Science Theater 3000 The Movie with Crow's escape plan:

Crow: [as he causes the ship to suffer the wrath of space vacuum.] Oh, wow, this is confusing! Hey, Mike! Can you hand me my calculations? [paper flies into his mouth] Thank you! Oh, well, look at that: "Breach hull, all die!" Even had it underlined!

• • Then lampshaded with his explanation:

Crow: Well, believe me, Mike, I calculated the odds of this succeeding against the odds I was doing something incredibly stupid and... I went ahead anyway.

• In The Rundown, the sidekick's "Thunder and Lightning" attack never works. He becomes dumfounded when it does work and needs a moment to think up the next stage of the attack.
• There are many such examples in the Marvel Cinematic Universe but none are quite so egregious as Thanos' Depopulation Bomb. Even discounting the fact that he clearly has no idea how overpopulation works, the Snap's survivors weren't grateful at all. All he did was traumatize the universe and cause governments and infrastructure to collapse after half their staff suddenly vanished. Rather than creating a balanced universe, he brought about mass destruction and chaos. The fact that the Snap killed off half of all life, including animals and microbes, means that he's further crippled food chains and increased health risks.
• Killer Klowns from Outer Space: While it wasn't wrong for Debbie and Mike to try to warn the police about the evil clowns that threaten humans, they didn't anticipate that the clowns might discover Crescent Cove and make it their next objective. And while Dave is friends with Debbie (hence her decision to try explaining the situation to him), this does not necessarily mean he'll believe Mike. But while Dave is indeed hesitant to believe Mike at first (feelimg jealous of Mike for dating your ex is understandable, after all), he does the right thing when he discovers evidence that Mike was telling the truth, a car that is suspiciously filled with cotton candy. (When Mike explains that the clowns killed an innocent teenage boy, Dave is inclined to agree with him.)

Literature

• The Hobbit: To enable the dwarves to escape from the Wood Elves, Bilbo secures them inside barrels so they can float away downriver. Unfortunately:

It was just at this moment that Bilbo suddenly discovered the weak point in his plan...Of course he was not in a barrel himself, nor was there anyone to pack him in, even if there had been a chance!

• • Not that being packed into a barrel himself would have been an improvement. Getting out again wouldn't have been easy.
• Twice in Kitty Goes to Washington. Kitty had good reason to banish Elijah Smith back where he came from, but she didn't consider that this would mean the collection of vampires and lycanthropes under his control would then be out of control. Cue chase scene, followed by calling in backup to deal with the fallout. Later, Kitty tries to distract the guards on the first floor of a building by throwing rocks at the upstairs windows, hoping they'll investigate the crash. She realizes belatedly that if they instead put two and two together and look out on the street, she'll get caught red-handed. (Luckily, they're typical guards.)
• In the Knight and Rogue Series, when told he must, in order to regain his legal rights, capture a murder suspect he released from jail and become his brother's steward, Michael sets out to bring the criminal to justice. Upon learning she's innocent he decides to not even bother with bringing her to trial, opting to be tattooed as a horible criminal instead. It's not until afterward that he realizes this will make people hate him by default and take advantage of him due to his being unable to go to the law for help. Bonus points for his father forcing the situation on him in the hopes that only his oldest son will hire Michael for a stable job if he's marked, as he apparently didn't notice that Michael spent the whole past year funding his adventures by stopping for the day in random towns and doing odd jobs for people who don't need to see the area on his arm where he gets marked.

Live Action TV

• An episode of Blake's Seven plays this for laughs with its justification: when Vila asks Tarrant if he can actually dock their tiny ship into the Liberator that they have just reclaimed from Servalan, the following exchange occurs. (Incidentally, it's just a throwaway gag, since the very next scene has them already back on the Liberator safely.)

Tarrant: I hadn't really considered it. Vila: What? Tarrant: I thought we'd be dead by now.

• In Buffy the Vampire Slayer, Spike schemes to both break up the Scooby Gang and plant evidence to lead Buffy into a trap. It takes the Big Bad he's working for to point out that he's given Willow the evidence, and Willow won't be speaking to Buffy now.
• In a Saved by the Bell episode, Zack has detention on the day of a trivia contest for a trip to Hawaii. He send's Screech in his place, who comes back to ask him a question. Mr. Belding explains only those in detention can talk to others there, so Screech purposely gets in trouble. When he sits down, Zack tells him the obvious problem with that plan.
• On an episode of Seinfeld Kramer is at a department store when he decides to sell the clothes he's wearing to another customer. When he's left naked in the store's changing room with nothing to put on, he whimpers, "I didn't think it through!"
  • Kramer does this kind of stuff a LOT. Like betting that he would turn his apartment into a triple tiered deck.
• An amphibious car challenge, Hammond's car looked like a boat (with the steering wheel near the back) with an upper portion for the "girls in bikini to go," which he then noticed was so high up he couldn't see over while driving.
• In the Doctor Who double episode "Aliens of London"/"World War Three", the Slitheen get into Downing Square 10, and chase (the Ninth) Doctor, Rose and Harriet Jones. The Doctor activates a defence mechanism that means there is 5 cms of thick metal between them and the Slitheen - or any way of escape. "There's no way they can get through." "And how are WE going to get OUT?" ... "Ah."
• In the Ghost Whisperer episode Love Still Won't Die, after Melinda gets contacted by the ghost of her ex-boyfriend Kyle McCall, not recognizing Kyle due to the fact that his body was darkened when he appeared to her in the antique store, Melinda goes to visit Donna Ellis and inform her of Kyle's death. When Melinda finally informs Donna of Kyle's death, she didn't realize that Donna and Kyle have already divorced before he died, resulting in a knee-jerking overreaction from Donna when she called in her actual husband. Melinda realized her mistake too late and left the scene.
• How Community is kicked off. Trying to get into Britta's pants, Jeff claimed to be a board certified Spanish tutor. He didn't realize that this meant she expected him to know Spanish. He also makes the mistake of confiding in Abed who clearly doesn't get that the whole thing is a lie and proceeds to invite people to the group.

Music

• Have you heard the story of Bottleneck Bob? He tried to rob the train with cattle, but evidently forgot they needed to be corralled somehow: "The cattle ran all over the place / And there was Bob with the longest face"

Newspaper Comics

• This Dilbert strip.

Video Games

• A frequent experience in Bomberman: Place bomb, walk into alley, realize alley is a dead end because of said bomb...
• House of Rules:
  • If Alexis has one fatal flaw, it is this. When the four employees sacrificed themselves so that Alexis could cast the Full-Resurrection Spell and revive Lady Jane, Alexis failed to take into account that leaving the bodies of the four employees in the same room with Lady Jane was a bad idea. Moreover, there is absolutely no indication that any of them had discussed using this spell with Lady Jane when she came down with tuberculosis, let alone obtained her consent for revival. If they had done so, they might have avoided so much tragedy.
  • Alexis herself admits that she and Ruth had failed to take extracting a fifth person's vitality into account, which is why she set up this entire system of luring prospective employees into the Mansion in the first place.
  • Alexis screwed up with the very first employee that she had lured into the Mansion, culminating in her beating said employee to death with a crowbar because she did not follow the rules and found out too much. Alexis failed to take into account that people tend to follow the rules when they are being watched, not when they are alone.
  • After killing that employee, Alexis realized that the mansion was too big to monitor by herself. So she used the Half-Resurrection Spell to reanimate the corpses of Pam, Colin, Greta and Ruth and to have them act as her eyes and ears. Alexis brought back Ruth first, and was so happy to have her back, but then she realized that it was not really Ruth, but rather a corpse that had to be programmed like a robot.
  • As a result of the system that Alexis had set up, hundreds of prospective employees were killed over the decades, just so one woman, who was in a coma, could live a little longer. If Alexis had thought things through at the very beginning, she might have been able to avoid all this tragedy.

• World of Warcraft:

Draenei Male: Step one, we land the Exodar. Step three, we defeat Legion and go home. There is only one detail missing....

• In Kingdom Hearts: Chain of Memories, Larxene is trying to cheer Namine up about the plan. Namine replies that they want part of Kairi to replace Kairi in Sora's memories so that he'll forget Kairi. Spot the flaw in this plan.
• Something you can do in Smackdown vs Raw 2011 ladder matches. Have you and your partner both climb up a ladder. The opponents get up and realize they could just tip the ladder over. Cue doing just that.
• In Rumble Roses Anesthesia created a robot that is meant to take over the U.S. military and at the same time is highly efficient at both humiliating and forcing female wrestlers into submission, yet she takes no measures to ensure that she herself can't fall victim to the very same robot's tactics (something that Benikage takes advantage of in the first game). In the sequel game she seemingly created new queens matches to further humiliate the Roses but once again didn't ensure she can't fall victim to the penalties herself.
• Wardwell House: In the second chapter, the Father thinks that he might be able to repair the boat with some of the fallen tree branches near it. Unfortunately, there is no indication that he has the tools necessary for that job. Justified, because he is dehydrated, starving, exhausted and probably delirious.

Web Comics

• An early strip of Sluggy Freelance starts off with Riff and Torg talking about how Zoe has a date with this guy she has a huge crush on. Riff then mentions that he is going to visit his ex-girlfriend Gwynn at her apartment, which she shares with Zoe. Torg is surprised that Riff going to see her alone like that. Riff insists that they're not alone, that Zoe will be there...at which point he realizes that even though he was aware of both of these pieces of information he only just now realized that they were related.
• Referenced in El Goonish Shive, but averted by discussing the plan before trying it, allowing someone else to point out the flaw ahead of time.

Female Immortal: I hate being invisible and intangible; it feels like cheating. Male Immortal: We can't exactly claim to be "everyday students" and expect to pass unnoticed in Elliot's house. Female Immortal: We could pretend to be burglars! That would make sense, right? Male Immortal: ... I don't think you've thought this through...

• • Abraham. Almost everything he ever did and we know about.

Raven: Every properly trained wizard has heard of Abraham, the idiot apprentice who recklessly enchanted a massive diamond instead of selling it to pay someone more skilled to fix his cursed noble friend.

• • • He claims trying everything he could to destroy it after it Gone Horribly Wrong. Only to be immediately asked whether he tried to chuck it into a volcano - c'mon, this didn't occur to him? Even if it would not burn, at least would be harder to reach.
    • And he swore to destroy every creature created by his botched enchantment on the assumption that the Dewitchery Diamond would be used against curses (like his werewolf friend), thus creating monsters. He hadn't accounted for the Diamond being used to rid people of harmless, if annoying, conditions such as Elliot's use of it to cure his Gender Bender problem by creating Ellen, an (mostly) innocent Opposite Sex Clone - this guy clearly didn't get classic education or much curse lore, if he never heard of Tiresias or that its criteria of "curses" is vague enough to include cosmetic magic (which was obviously bound to happen - and did, to the second DD's "victim" shown).
• Webcomic/webgame Wicked Awesome Adventure points out how often this befalls adventurers in the course of escape and exploration.
  • J.E.T. enlists the help of a wounded and unwilling Candimp to disarm a trap.
  • Rhys solves a puzzle to access a new area of the Haunted House for exploration- opening a trap door, too.
• Girl Genius got a few examples. Like this guy.
• This appropriately titled Order of the Stick strip.
• Fontes' Rants: Fontes uses the Life Note, a Parody of the Death Note which creates a life form he writes in it, to create an Ax Crazy Marty Stu character. When he recovers after inevitably being knocked out;

Fontes: ...I really shouldn't have made him able to summon firearms...

• From Super Stupor, this strip, after Punchline explains why The Anarch's plan is really just Suicide by Superhero:

The Anarch: I may have made a slight error in my calculations. Punchline: When you were adding up the numbers, did you remember to carry the stupid? The Anarch: Yes! ...no.

• In Schlock Mercenary, the UNS tries to use a court case to capture under a good-looking pretext the company that accidentally acquired illegal (and as it turned out later, also scandalously secret) military/medical technology. A nearly-all-powerful AI plainly states that it's not a question whether they have it. They do. The real question is - do UNS want all the details of it to be published as a part of the extradition process? Then they try to use this opportunity to trick said godlike AI into admitting that he has been performing morally questionable actions (specifically, "disappearing" problematic people).

Kerchak: And Then What? Breya: I...haven't thought that far ahead. Kerchak: I'll bet you a bushel of pureed bananas he has.

• • Schlock was left behind when the team gone outside on an airless planetoid because he haven't Powered Armor. Then he noticed EVA suits rack... "Sergeant Schlock poured himself into an emergency exosuit and jumped into a 6200 meter deep excavation. Local acceleration is 9.114 m/s^2. This exosuit has no flight system."
  • Murtaugh wanted to short-circuit stormy atmospheric layers using her plasma gun.

Ebbirnoth: Doesn't that path lead right back to you? Murtaugh: Give me a moment. I really want for this to be a good idea...

• • A copy of crazy AI running on hardware controlled by another AI pulled the old "Help, I'm trapped in fortune cookie factory" trick. The host points out that this simply means it's known to be compromised now.

- You do realize you've just killed both of us, right? - Oh, dear, you didn't allot me enough of processing power to see that coming.

• The Ruby arc of the original Nuzlocke Comics has Maxie releasing Groudon to "end all water"... and then dumbfounded when people start dying of heatstroke.

Maxie: I don't understand... how could water be good?

• Exterminatus Now had Virus prepared to exorcise a daemon-possessed toaster. With holy water.

Web Original

• In The Salvation War, after the demonic general Abigor hears of the defeat of (most of) his cavalry attempting to charge a ridgeline with "cowardly mages throwing mage bolts, with mage-bars in the ground and silvery snakes in the ground that cut up demons and their steeds alike" (paraphrasing here), his plan for the second day of fighting is to extend his lines by thinning them—by the time he was done, an almost-fifteen-mile-long front! — so as to outflank and envelope the enemy, while ordering massed use of demonic bolt "fire" to suppress the mages. Too bad he didn't realize that he would only be able see a small portion of the battle at any one time, and thus would have to keep riding back and forth along the lines, until he was already on the front lines in the midst of the carnage, with multiple rockets headed his way... they missed him, but he immediately and correctly intuited that he had been personally targeted.
• Kevin Murphy puts the exact phrase into the mouth of the Scott Ian-looking Geat who makes a spectacularly failed attempt to charge Grendel in the 2007 Beowulf Rifftrax.
• In Dragon Ball Abridged Gohan suddenly realized mid sentence that his decision to challenge Recoome to a fight after Recoome had already wiped the floor with Vegeta, a much more powerful fighter, was a bad idea.

Gohan: I'm not going to back down. I might be younger than you, smaller than you, weaker than you, and much less experienced, but I learned more about peach farming than yo-I think this was a horrible decision. Recoome: Recoome agrees.

• Early in Yu-Gi-Oh the Abridged Series, Mokuba laments his poor foresight upon realising that using a Bedsheet Ladder generally only works if the sheet is long enough to reach the ground floor. Fortunately for him, he's a cartoon.
• The Spoony One puts this in the mouth of the main villain of Highlander the Source when he gets the Quickening at the top of a tall tower.
• In the Team Fortress 2 Team Service Announcement videos, the Engineer decides to build a sentry and dispenser, then fall asleep. However, he forgets about the spy, who can sap sentries and dispensers and destroy them of the engineer doesn't pay attention.
• The plan that Leeroy's raid group comes up with for taking on the Rookery in the Leeroy Jenkins Video ignores two key facts:

1. 1. Scattering the whelps of the Rookery only keeps them off you for a few seconds and will likely bring more to bear on you—you really want to hatch as few of them as possible. Fear rotation is rather pointless in the Rookery anyway due to the rate at which the eggs respawn.
   2. The paladin ability Divine Intervention does not allow a protected character to use any skills and is very much wasted on mages (who primarily rely on skills such as AOE attacks) and has the added "bonus" of killing the paladin who uses it, removing a character with the ability to tank and heal from the general fight.

• Half of what Jay does. For example, breaking into Alex's home. He drops his flashlight, and then runs into the Operator.

Western Animation

• In one episode of Justice League, Copperhead attempts to gain leverage for an escape by jumping onto Hawkgirl's back, positioning his poison fangs near her neck, and ordering her to fly him out. She flies up a few hundred feet and stops. When Copperhead demands to know why, she notes that his threat is no longer as effective, since if he bites her neck she'll fall to the ground and they'll both die. "Didn't think this through, did you?" After she touches down, Green Lantern congratulates her on the bluff; her reply is a deadpan "Who's bluffing?"
  • In another episode, Downpour, a pastiche of one of the Wonder Twins, tries to kill Aquaman by hitting him with a torrent of water. Aquaman just stands there with a raised eyebrow: "'King of the Seas', remember?"
    • Downpour's follow up wasn't particularly well thought out, either. He rushes up to Aquaman and punches him. Ineffectually. Aquaman responds with a backhand slap that takes Downpour out instantly.
• Invader Zim:
  • Zim has this as a personality trait; as The Other Wiki once described him, "Zim has a crafty sort of intelligence, but he tends to think precisely one step ahead of his current problem". For instance, Zim builds a stasis-field device in one episode which subsequently explodes, but the fireball is slowed by the stasis field until it's expanding at less than walking pace. However, it will eventually grow to the point where it'll consume Zim's base along with the entire city. Zim's brilliant plan to stop this? Simple. He'll just cancel the stasis field. Despite being warned by his computer, and even his Cloudcuckoolander sidekick, that this is a really, really bad idea, he goes ahead with it. Hilarity Ensues.
  • The Tallest also seem to suffer from this, resulting in conquered planets being turned into massive parking lots because they didn't know what they'd do with the planet after conquering. They also ordered enslaved races to build weapons for them, resulting in the Megadoomer needing a massive extension cord and cloaking everything but the pilot and said extension cord.
• Family Guy:
  • In the episode "Blind Ambition", there is clip of one of Peter's (or both his) Siamese twin ancestors each fighting opposite sides in the Civil War. The one who fought for the Union killed the other, who continued decomposing until he was a skeleton. "Nope... Did not think that one through," he said to a bartender who asked about the skeleton.
  • In "Don't Make Me Over", the guys form a band. Just as they start their first gig, they realize one problem with this idea: they don't know any songs.
  • In a broader sense, this is Stewie's Fatal Flaw. He talks big and gives out tons of advice but never thinks it through past the short term. Whenever he reveals some big trick to someone, it never occurs to him that they might be able to use it against him.
• In the American Dad! episode "Francine's Flashback", Francine gets poorly-aimed Laser-Guided Amnesia, she runs off to Burning Man with Haylee's boyfriend. This exchange happens when Stan meets up with Haylee at Burning Man:

Haylee: Mom stole my boyfriend! Stan: Your boyfriend stole my wife! Let's get back at them by dating each other! Wait a minute. Daddy didn't think that through.

• SpongeBob SquarePants: For a protozoan who goes to college and makes highly elaborate plots to get the Krabby Patty formula, Plankton can be a little slow when it comes to thinking ahead of his goals. For example, a robot made to look like a customer enters the Krusty Krab. Eugene Krabs, smelling an obvious trap, takes the place of the register. To his astonishment, the robot just asks for coral bits and even pays him money after its given its order. Suddenly, Plankton, who somehow managed to hide INSIDE the dollar bill (even for someone his size, there must have been some Hammerspace in there), pops out and gloatingly order Krabs to hand him the secret formula. Krab's response: "Or What?" Plankton: "I don't know. I never thought I'd get this far." Krabs: "Well then, allow me to suggest your next move" (flushes him down the toilet).
• The Jimmy Two-Shoes episode "The Big Drip" has Lucius destroying every washroom in Miseryville to torment Jimmy during a Potty Emergency...including his own.
  • And pretty much any plan Jimmy and Beezy devise (alone or together) without outside input.
• Avatar: The Last Airbender: Zuko, such as when he kidnaps Aang in the North Pole in the first season finale or when he tried to steal Appa from Lake Laogai. He gets better, eventually.
  • Zuko's so bad with it that it's contagious.

Zuko: I thought you thought this through. Sokka: I thought you told me it's okay not to think everything through! Zuko: Maybe not everything, but this is kind of important.

• The Bugs Bunny cartoon Jack Wabbit And The Beanstalk has Bugs challenging the giant to a duel. "Take twenty paces, toin, and fire. Got that, shorty?" As the giant takes his paces, he disappears into the horizon and Bugs thinks he's outsmarted the giant. But then the giant reappears over the other horizon—the twenty paces were enough to circumnavigate all the way back.
• From the "Dog Of Death" episode of The Simpsons

Homer: I've figured out an alternative to giving up my beer. Basically, we become a family of traveling acrobats! Marge: ... I don't think you thought this through.

• From the "Her Parents" episode of Adventure Time

Jake: Nah... That could never happen. Finn: You didn't think this through enough. IT COULD HAPPEN!

• Turned into a Running Gag with Mojo Jojo in The Powerpuff Girls. To the point where when a spree of robberies occurred in Townsville, the girls automatically ruled out Mojo because it was too well thought out.
• Wacky Races - Every single time Dick Dastardly Stops to Cheat. It's never enough that he is ALWAYS miles ahead of every other racer, he not only has to stop to lay a trap, but also stays behind to see the payoff, which ALWAYS puts him in last place. The most absurd example was the episode where he got stuck in the mud, and pulled out by a farmer with a donkey. He decides to buy the donkey, thinking that the farmer will no longer be able to pull the other racers out. Never mind that 1) almost half the racers have some gimmick that allows them to get out on their own, including a dragon that can dry it up completely, 2) the farmer OBVIOUSLY has several beasts of burden besides the one he sold and 3) Just what the heck will he do with a frickin' donkey?!
• In The Avengers: Earth's Mightiest Heroes, Absorbing Man occasionally absorbs things he really shouldn't. When fighting the Hulk as metal, he absorbs rock. The Hulk promptly breaks his arms off. The metal form might not have let him win, but was at least keeping him in one piece. Much later he absorbs Mjolnir, and Thor reveals that he can now control Absorbing Man just like he does Mjolnir, and starts hitting people with him.
• In an episode of Rugrats the babies imagine shrinking down and traveling into Chuckie's stomach to take out a watermelon seed he accidentally swallowed. Angelica however reveals her intention to actually water the seed so it grows and causes Chuckie to explode. She succeeds and gloats evilly, until Tommy points out it's going to explode with her inside it.
• In the ThunderCats (2011) episode "The Forest of Magi Oar," the young hero Lion-O begins to recognize and Lampshade Hanging his own lack of forethought. When he uses his gauntlet's Grappling Hook Pistol to latch onto a retreating Giant Flyer Viragor, Lion-O has just enough time to realize "maybe this is a bad idea" before he gets violently dragged along for the ride. Shortly thereafter, he faces down the charging Big Badass Bird of Prey after tossing his weapons aside. Again, he muses, "probably another bad idea," seconds before it grabs him in its talons. The latter gamble does manage to pay off, since, on a hunch Lion-O is betting Viragor proves Dark Is Not Evil.
• One of the antagonists's names in Bob's Burgers is named Logan Berry Bush. His mother outright admits she and his father didn't think it through when they named him.
• In the Kim Possible episode "Ron Millionaire", both Ron and Drakken are guilty of this. Ron was dumb enough to carry $99 million in his pants and Drakken's "Operation: Catastrophic Doom" involved positioning two mirrors next to each other on the moon causing his super laser to fire back at itself, destroying his brand new lair.
  • In "Queen Bebe", both Kim and the Bebes are guilty of this. While Kim was admittedly prepared for a fight, it wasn't smart of her to enter the Bebe Hive alone, as her enemies would have a home field advantage. And it's entirely possible for her Kimmunicator to be taken from her, regardless of whether she was armed or not. Not to mention she was fighting three against one, so when the Bebes work together, she ends up trapped on a deadly conveyer belt. But truth be told, she had her reasons for thinking she had to fight alone. But thanks to Rufus's new super speed shoes (which Kim herself had), she ultimately didn't. And that's where three of the Bebes' downfall comes in. When they allowed a "disgusting creature" to distract them, they forgot about Kim (who was still trapped) more or less completely, which itself allowed her to turn the tables and destroy them. And yes, Kim herself lampshaded that.
• Rick and Morty:
  • Morty calls out Rick for this in "Full Meta Jackrick" when he released Rhett Caan, a being capable of pulling Cosmic Retcons, without any kind of safeguards or assurances. Rick doesn't push back on that, admitting that he royally fucked up by doing so.
  • Evil Morty accuses Rick Prime of this in "Unmortricken". Subjecting Diane to a Cessation of Existence is a sure-fire way to not only give his wife a final middle finger and prove how much smarter he is than other Ricks but, since Prime wanted to be left alone, it also painted a massive target on his back as Ricks who loved Diane now began hunting him for revenge.
• As Starscream, of all people, points out, Megatron's master plan in Season 2 of Transformers Animated is a fine example of this. Having acquired the blueprints for a space bridge, Megatron ordered his army in space to attack outlying Autobot colonies to spread thin the Autobots' military forces. With Cybertron now under-defended, Megatron will use his bootleg bridge to warp directly to Cybertron and bring his army there via the Autobots' own Portal Network. At no point during this elaborate planning process did he ever consider that the Autobots might have a remote shutdown for the space bridges and could use it when the Decepticons got too close for comfort.

Real Life

• Most people make this mistake in everyday situations when they know the results of a missed variable can be ignored or worked around (e.g. if you reach for a tool that you forgot to prepare, just get up and retrieve it). Bad things tend to happen only when too many of such mistakes line up and cause a chain reaction.
• Water ruins the radar-absorbent coating of the F-22 Raptor. You can fly it in the rain all you like, it just won't be a stealth fighter afterward. The designers were aware of this flaw, it's a result of an inherent limitation in the materials, not a lack of foresight.
  • In fact, many military projects fall into this, as it often appears that the designers seem to have a tendency to be so enamored with their new project that they forget to take various practical issues into consideration. Of course, that doesn't mean that the projects aren't worthwhile, with the benefits outweighing the problems. Also many of the ones that don't seem to have been thought through are in fact stepping stones towards more reliable applications of the technology.
  • The F-22 for example was a development on the earlier stealth aircraft, the F-117 and B-2. The B-2 needed vast climate controlled hangers to keep its stealth working, while the F-117 necessitated it traveling relatively slowly (sub-sonic) to maintain stealth. The F-22 also needs climate controlled hangers, but much smaller ones than the B-2 and it can fly twice as fast as the F-117 while being even harder to detect. The F-22 is certainly a high maintenance aircraft, but is also the most stealthy (lowest radar cross section) of all manned aircraft, and will probably remain so for some time to come. The next stealth aircraft (the F-35) has in fact taken the stealth and speed down a notch in order to make the stealth technology more robust. The idea being that the F-35 will be able to have as little downtime as conventional attack aircraft while maintaining a good degree of stealth.
    • It is also worth noting that while the US government is happy to sell F-35's to other nations, the F-22 remains a state secret. To give you an idea of why... When the F-117's flew over Iraq in 2003 they were ridiculously good at penetrating air defenses (They made up 3% of the aircraft and hit 30% of the targets in the first 24 hours) and what with the F-22 having about 250 times smaller radar cross section and can fly faster... Yeah. She needs a lot of love, but she's way too good to trust anyone else with.
• A rather better military example would be Project Pluto, the supersonic low-altitude nuclear-powered nuclear ramjet missile developed by the U.S. military (the fact that they seriously considered building that thing counts already). Project Pluto's real problem was that it was overtaken by ICBMs during its development. Aside from the difficulty in test firing it (which wasn't as crippling as it sounds, it might be an environmental disaster on wings, but this is during an age predating the green movement, meaning that a bit of isolated water in the Pacific would do), the project had a serious chance to turn out as a practical nuke 'em to hell option. Its just that ICBMs are more practical, being faster, cheaper and harder to intercept; they may not irradiate such vast swaths of enemy land by merely flying over them, but once the major cities are gone, that hardly matters anyway.
• Australia's problem with the Cane toad. Because of Cane beetles destroying sugar cane crops, a bunch of Cane toads were imported to get rid of them. Only problem was that the toads couldn't even jump that high, so they ended up being unable to eat the beetles that were on the tall stalks... which caused them to eat everything else. And then they started infesting and taking over... combined with how they're highly poisonous and can poison any animal that eats them. Yeah, that solution was not exactly the best thought out.
  • It doesn't help that cane beetles and cane toads aren't active at the same time of day, so they don't ever even interact.
• Another Australian one: The Murray River was destroyed in an attempt to bring over European farming techniques without realising that Australian soil was ill-suited to the endeavour. Clearing of trees for land led to salt buildup, which poisoned the water and ended up clogging the river.
• And yet another: Despite already knowing that Australia is the driest continent in the world (seriously, check out the sheer amount of desert there is), no government there had a sufficient water-saving plan aside from the restrictions. This came back to bite them in the arse when the country was engulfed in an extreme drought, the likes of which had not been seen for the past several centuries. Of course, now they have the exact opposite problem...
• The Lake Peigneur disaster was caused by someone drilling for oil through a lake into a salt mine. Admittedly, they knew not to drill through the salt mine and just messed up when they were figuring out where to drill, but still.
• During WW 2, the Russians strapped explosives to dogs trained to run at tanks. Once the tank ran over the dog, the pressure-activated explosives would total the tank. The only problem? They trained the dogs using Russian tanks made to look like German ones. But Russian tanks used diesel engines; German tank engines used petrol. When in doubt, they went with what smelled familiar. Hoist by their own petard indeed.
  • The Dog Bites Back. Though this is RUSSIA in World War II, the only reason they weren't using human suicide bombers was because dogs are quicker and smaller.
• A salesman showing reverse searching (which was a search for what people were searching the internet for) decided he would use "toys" as the keyword. Apparently, he didn't realize until too late what kind of toys people search the internet for from the privacy of their own homes...
  • Considering Rule 34, it would have been smarter to just skip the demonstration altogether.
• Quaker Oats buying Snapple for $1.7 billion. Unlike every other drink in Quaker's line-up (including, for instance, Gatorade), Snapple has to be refrigerated. It was only after the deal had gone through that Quaker realized that it had a shipping fleet of exactly zero refrigerated vehicles. Refrigerated distribution outlets soon realized this as well, and colluded on a high price to deliver the Snapple. Eventually, Quaker would sell it for $300 million dollars to another company, long after Snapple's trendiness had faded.
• Nazi Germany had a problem: with the US being officially neutral but unofficially supporting the Allied war effort, German u-boats could not be used to their full effectiveness in the Atlantic. Japan attacks the United States and war breaks out, and Hitler thinks this solves his problem as he can declare war on the US because Japan is an ally, and thus finally give his naval forces the freedom they need to effectively cut off Great Britain. Of course, this also means the single largest economic and manufacturing power on the planet now doesn't have to pretend to play nice either.
• Criminals. This tends to happen to them a lot. In example:
  • A few would-be ATM thieves in South Africa decide to use explosives to open up an ATM. Once the bomb goes off, the money would be theirs for the taking! But, somewhere in thinking how awesome it would be to blow up an ATM with a bomb, they forgot to make an important consideration. Namely; paper money tends to burn. Hilarity Ensues.
  • There have been several cases of people walking into a business, filling out a job application with their real name, address, etc., and then holding the place up at gunpoint. Of course, it doesn't take too long for the police to find them.
  • One example was a bank robber who decided to rob a bank, that was across from the FBI headquarters, ON PAY DAY. Oops.
  • Another robber went up to a bank with a stick-up note...written on the bottom of his pay slip, which had his name, address, postal code, and telephone number on it. Of course, he doesn't compare to the robber who held up the bank coming right from his work at a construction site...still wearing his hard hat, which had his name on it. Neither of them are quite as stupid as the criminals who decided to draw masks on their faces with black marker.
• Official policy of communist states to deal with disaster? Issue a nationwide bulletin that absolutely nothing has happened, and everything is fine, and censor any attempt to bring it to the public's attention. Well the public still became aware of it, but by that time, it was too late to do anything about it.
  • Biggest example: The Chernobyl Disaster. It was one of many things that lead to The Great Politics Mess-Up.
  • The resultant policy of Glasnost the Soviet Union enacted after the disaster is another example, but in the reverse. Turns out, when you can't even feed your own people, enacting a policy of total transparency with the press is not such a good idea after all.
• The Mongol Invasion of Japan. Kublai Khan was in such a rush that he ordered the Chinese boat builders to make a huge fleet (a fleet second only to the invasion fleet that launched the Invasion of Normandy) within a single year. The Chinese laborers had to suplement the sea-worthy boats with river boats that had no keel, and thus were unworthy for sea travel. Bad enough when you are crossing an ocean, even worse when that ocean is prone to violent storms and typhoons. The now-famous kamikaze lead to the single greatest loss of life in a disaster at sea in recorded history, with many of the over 3,000 ships sinking with most of their crew.