The Village. M. Night is legendary for his twists and sometimes they work and sometimes they don’t. The Twist at the End of the Village was just so terrible. Leading up to that the movie had such great atmosphere, characters and man the mystery of the creatures was incredible. And then the ending happened.
The Wolverine (2013). This movie was setting things up so nicely and had a lot really great movie parts and then the ending was a one on one fight with the Silver Samaria. Everything about the final fight was just dumb.
The Faculty. The movie is basically a remake of Invasion of The Body Snatchers confined to a high school and does some really fun things with the story and then unfortunately the ending happens. The druggy outsider character is now the football team’s quaterback and is fucking his teacher, the psuedo lesbian is now dating the once was Jock meathead who is now an academic. It was such a bizarre tacked on wtf resolution.

AND THE KING OF SHIT ENDINGS IS….

SUNSHINE two thirds of the movie is a really great looking moody, exploration of a long term space mission to save the world and the final third of the movie becomes Friday the 13th. Then again Danny Boyle has a long history of fucking up his movies endings.