My vote goes to A Clockwork Orange
I'm with Mrs. Duke on that one!Back in the early 2000s, I bought a DVD copy of Clockwork Orange for a buck at a garage sale. Mrs Duke, having no clue about the movie, suggested we watch it that evening. I could tell she was somewhat perplexed, but the scene where Alex beat the cat lady to death with the huge porcelain phallus was too much for her.
That must have been funny to see!Death Race 2000 with David Caradine was so bad that people in the theater started throwing stuff at the screen and the management offered refunds to those that wanted them and left before the movie ended.