I see very few movies in theaters that I don't like because I am generally pretty picky about what I see. I did see Daredevil (Ben Affleck) for free, and that was a rought one. I think I was probably most disappointed with The Dark Knight - I might have walked out of that if I had driven myself. Also, Michael Bay's first Transformers movie was just horribly bad.
I did go see Snakes on a Plane and was disappointed, not because it was bad, but because it was not bad enough! I had expected it to be just the most attorcious B-Movie scholck, but it's actually a reasonably serviceable action flick. Too bad.