American Pyscho
It's no secret that Patrick Batemen is a psychopath and possibly violent sociopath. He's going through a severe mental breakdown with the coolness of cucumber in most scenes. His narration of the events is unreliable, which would explain why he was so convinced that he went on a killing spree even though he really didn't.
Arrival
Amy Adams's character in the film is complicated and hard to understand. She's seeing visions of what we thought was her past, but it was actually visions of Louise's future, which makes most of the confusing parts make more sense. The ending is interesting because only she and the viewer know what is really at stake.