A Scanner Darkly and Batman Forever.
The visual style of A Scanner Darkly made me motion sick. And in case of Batman Forever the sound was way too loud for the small cinema. It was one of my first action movies and it felt like torture to me.
I never walk out just because a movie is bad, because I have payed for the ticket and want to know all about it when I complain about the movie later.
Where do you prefer to sit in the cinema?