There's nothing quite like a good film. Multiple acts of build-up centered on endearing an audience to characters, putting them through an arc that culminates in a satisfying conclusion that lets the viewers leave the theater with thoughts provoked and minds gratified.
One of the most effective methods of making a satisfying ending is the surprise twist. Done well, this can elevate the stakes of the third act by pointing out clear signs that the audience never picked up on culminating in a shocking reveal. But done wrong, this can tear down the suspension of disbelief by negating previous plot points, abruptly changing the tone of the movie, or being just too ludicrous to stomach.
While a weak or lame twist can be disappointing, it is downright tragic when the film was gearing itself up for a big, emotional ending that would have left one last dramatic impact on its audience. Seeing how a film could have had a potentially great finale but was ruined by a pathetic attempt to surprise the audience for no reason leaves the viewers more confused and upset over what could have been than satisfied with what they recieved.
10. It Was All A Dream - Savages
Savages is an example of a good movie with a perfect ending that is completely undone by an additional five minutes tacked on that is so detrimental that it doesn't just ruin the final act of the film, it pretty much negates the entire movie preceding it.
Based on Don Winslow's primal novel, the film looks like it will end the same way as its source material. After running from the cartel and abandoning any morals they may have once had, Californian drug dealers Ben and Chon confront druglords Elena and Lado in an attempt to save their kidnapped mutual girlfriend Ophelia. Things go south, as confronting the cartel often does in movies, and Ben is fatally wounded. Too distraught to go on without their partner and accepting that the world cannot contain the wildness they aspire to, Chon and Ophelia deliberately overdose so they can join Ben in death.
Except they don't because that ending was just a bizarre fantasy Ophelia had about the whole affair. Instead, the last few scenes of the movie explains, things went down pretty smoothly all things considered. Elena is captured, Lado escapes but is done messing with the trio, and they all move to a pacific island where they live out their days as peaceful savages.
Everything about the ending screamed that it was a studio note and was so distracting that it outright ruined the movie.