Award Snub: An odd example. When Jamie Foxx was nominated for for Best Supporting Actor, a few people protested that he should have been considered the star of the movie, and that Tom Cruise only got top billing because he's better known.
Badass Decay: Vincent goes from being a cold-calculating hitman who can perform the improbable aiming feat mentioned below to a simple thug with a gun when he goes after Max, a common cabbie. Since the movie didn't want to have a The Bad Guy Wins ending, they suddenly gave Vincent a course in the Imperial Stormtrooper Marksmanship Academy. Possibly justified since Vincent has been shot in the head right before the climactic chase, causing him to undergo something of a villanous breakdown.
In the final shootout on the MTA train, Vincent's trained, straight shooting ends up hitting the part of the metal door between the two windows, whereas Max's untrained, relatively chaotic shooting ends up penetrating the windows and (eventually) hitting Vincent.
Though this all could be justified since Vincent was still going after Annie even badly injured but with Max there and protecting her, Vincent started to slowly lose it to the point of losing focus, which would be something he would never do.