i'd have to say the movie that actually made me get up & walk out was "House of the Dead" that movie is so bad that the director should have been thrown into a pit of his own lame zombies. 'nuff said.
I have only walked on on one movie in a theater. I was real young, like maybe 11. I was at a double feature with my dad and the second movie was "Real Genius". We lasted about 20 minutes, until Chris describes his "penis stretcher" and my dad had just had enough. He was thoroughly disgusted. That movie went on to be one of my favorites as a teen and young adult.
Recently I watched a DVD that was so bad I turned it off after about an hour. It was a movie called "Factotum" that was loosely based on the life of Charles Bukowski. It got pretty good reviews but just pretty much failed in every way for me.
I can understand finding that movie distasteful, but seriously it was marketed as the most savage, brutal, gory movie to date. I'm curious what you were expecting.