The Elder Scrolls IV Oblivion/Tear Jerker

• When you're too late to save Lucien, and you never get to clear his name, either.
  • The Dark Brotherhood quest the Purification: you have to kill all of the members who have come to love you like family. This is made worse by the fact that you later find out there was no traitor — at least not in the Cheydinhal Sanctuary. You killed them all for nothing.
    • Made even worse with M'raaj-Dar who is a total jerkass to you right up until the beginning of this quest where he decides that the two of you got off to a bad start and wants to try and be friends.
• The end of the Thieves' Guild quest line when you meet the Gray Fox in Anvil and he reveals himself to be Countess Umbranox's long lost husband, Corvus.
• The quest A Brotherhood Betrayed. Three adventurers found an ancient amulet, but one wanted it for himself. So after many years, that traitorous adventurer murdered the other two in the guise of a vampire hunter, setting the other two up as vampires. The wife of one of the victims, shocked by what had happened, asks you to help. After the truth has been revealed and the seemingly mundane amulet retrieved, she reveals that the other two knew what the traitorous adventurer had been planning, and cursed the amulet so it becomes mundane. The secret word to lift the curse? Brotherhood.
• The penultimate quest of the Fighter's Guild requires you to infiltrate the Blackwood Company and learn their secrets. As part of the quest, you're required to drink a bottle of Hist Sap, a hallucinogenic drug, and help the Blackwood Company clear out a town of a goblin infestation. When you return to the town after the drug wears off, you find that in your hallucination you mistook the innocent inhabitants and their sheep for goblins and slaughtered everyone in the town, including Biene Amelion, who you helped out in a previous quest. Her father, who you freed from jail by helping cover the cost of his bail, wonders what kind of monster would do such a thing...
• This may seem more like a Troper Tale, but bear with me. While heading for a quest outside Anvil,near the local Oblivion Gate, I found an Imperial Legionnaire standing between two corpses. One was his horse, the other a Clannfear. It couldn't have been clearer what happened. He stared down at the blazing gate for a full two minutes, almost like he was making a decision. Then, without warning, he whipped out his sword and charged into the Daedra down the hill, screaming "For the Emperor!" as loud as he could. He died quickly, but still, damn.
• The ending if you became fond of Martin. You went to such lengths to help and protect the guy and he has to sacrifice himself.
• Another Dark Brotherhood quest, The Lonely Wanderer, makes me tear up every time I have to do it. To find Faelian, you have to ask around for info, and end up at the King and Queen Lodge in the Talos Plaza District of the Imperial City. You talk to the innkeeper there about him, and she mentions how he has a wealthy girlfriend that's apparently devoted to him. You talk to the girlfriend (possibly needing to chat her up into a friendlier level), and SHE tells you all about how even though Faelian's a penniless Skooma addict, she still loves him and hopes he manages to someday clean himself up before he gets himself killed. All this to corner Faelian and kill him. Makes this troper feel guilty every time.
• For this troper, it was the aftermath of the Baenlin assassination. The assassination went off without a hitch, and I was feeling pretty damn smug. I did a few more missions for about one in-game week... and then I walk into the Grey Mane, and see Baenlin's Gentlemans Gentleman, Gromm, sitting there and crying into a beer. And it hits me: He's been sitting here, getting drunk and crying for a week. Because of me. I did that. I killed a man, and I caused his dependents immense pain, for a few hundred septims I didn't really need. And I felt good about it. Cue erasing save file and starting over.
  • This was even worse in this troper's playthrough of the Baenlin assasination, where, a day or so after experiencing the very same heart-wrenching scene in the tavern listed above, I witnessed Gromm charge at a number of Legionnaires in what can only be interpreted as a drunken fit of sorrowful rage, where he was quickly cut down. I realized that- digital or not- I just drove someone to commit suicide by police. I quickly erased my save and decided to stick to the Thieves' Guild from then on.
• There's a Fighter's Guild Quest where you read Viranus Donton's journal. He writes about how he thinks his mother doesn't think he's as good as his recently-killed brother. You find the journal when you find him dead in a mine. The final entry? "I hear trolls I'm sorry Mother".
• In the Shivering Isles expansion, near the end, as Sheogorath turns into Jyggalag. Hearing the wacky, crazy, eternally-cheerful Sheogorath speaking in an orderly, logical manner and sounding so depressed.... And then he sadly tells you to get out while you can, or he'll kill you.... It's heart-breaking, really.
• You can find a dead troll under a bridge. Funny? Yeas, until you read the note on it's body.

"Mee wurst troll evurr nobuddy pay brijj tole me nott sceary enuf mee gett drunc an kil sellf troll droun" Yep, this troll just committed suicide. All in the name of Billy Goats.

• After triumphantly destroying the Great Gate, I emerged onto the battlefield to find that almost everyone had survived! Then I looked down, and saw the body of Jauffre. What's worse, he's still tagged as a quest object, so his body never disappears. Now every time I walk around Bruma, I keep stumbling across his corpse.