We rarely go to movies. Mostly rent or wait till they come on HBO. So, I hardly ever see a movie I don't like. If I don't like it, I turn it off, or in the case of things like the Piano or the English Patient or Mars Attacks, I simply never even think about watching them.
I like comedy- I'm a huge 3 Stooges fan, so stuff like the Naked Gun movies, parody stuff, Mel Brooks movies are all great to me. I also like any Arnold movie in all of his glorified cliche-ness.
Something that was so bad that I actually kept watching was some old anti pot movie called "Maryjane" starring former teen heartthrob Fabian. It was about a teacher who is trying to stop kids from smoking pot in the early 60's and he gets arrested for having pot that someone planted on him. He's trying to save this one kid from the dealers, and in the end the other teacher who was his girlfriend was the main dealer and was a heroin junkie. The moral, which we all know, is that that if you smoke pot one time, the next day you are out beating up old ladies for heroin money! It was so bad it was actually funny.