Walked out of Free Guy, Signs, About A Boy, Scary Movie (I don't know which number it was), Reign of Fire, and God knows how many terrible festival films.
I left my partner of the time watching the first Lord Of The Rings film while I went for a pee and wound up having a hot dog and reading the paper outside for half an hour (I missed nothing and slept through the rest).
The Core was so execrable I stayed to see if it could get worse (it did). At one point the sound failed and they had to stop it, and the audience cheered.
Bit niche, but the Tulpa screening at FrightFest in 2012 (I think) remains legendary. The director and cast were in attendance and the whole crowd howled laughing all the way through it, including me. It was not a comedy
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