No. 1: Howard the Duck
Howard the Duck - I have a real problem with talking, upright ducks. However, the movie didn't bother me that badly...until Principal Ed Rooney (Ferris Bueller) turned into the deformed evil bad guy at the end of the movie. His voice and his face made me instantly regret watching this movie. Even the scene with Lea Thompson's butt couldn't replace the horror I was witnessing on screen. This scene/image has stuck with me my whole life. Once again, irrational, I know...but you can't help what image's are burned into your mind.