The Ending
I almost liked this movie. sure the acting wasn't all that great in some areas (the dentist was the worst character in the film IMO) but I liked the plot, I liked where the story was going, and I especially loved the first of the 10 *beep* twist they tried to throw at us. After that the film went from unpredictable to completely predictable in seconds... The ending is the most important part of the film for me, if the whole movie is good but the ending sucks, then the whole thing is ruined.