10 Horror Movie Secrets They'll Never Tell You
9. What Was Real & What Was A Dream? - American Psycho
American Psycho's big ambiguity has been debated to death, namely whether or not the killings carried out by Patrick Bateman (Christian Bale) and the increasingly unhinged sights we witness throughout the film actually happened or are in fact mere fabrications within his own insane mind.
Director Mary Harron has spoken at length about the film and especially its ending, but she's refused to explicitly confirm what was real and what wasn't, believing that doing so would "take the movie away" from the audience.
She did however tell Charlie Rose in an interview that she felt it was a failing on her part as a filmmaker that some audiences came away believing the entire movie to have been a dream.
Harron added that this wasn't her intent and she wanted to end the movie on a note where it's clear that the story is a mix of reality and delusion, though has sensibly shied away from confirming which parts of the movie are which.
One can reasonably suggest, though, that all of the killings basically happened, but perhaps not in the outlandish fashion they did in the film, and by the time Bateman's trying to feed a cat to an ATM machine and blows up a cop car, it's purely in his mind.