Donnie Darko
Personally, I really enjoyed this movie. Although I didn't understand some parts, I can still give my opinion. To me, Donnie is a young man with mental health issues, obviously. The fact that he has an imaginary friend named "Frank" is very important. Donnie was never forced to do anything he did; he did it because "Frank" saved his life at the beginning of the film. As the story progresses, you realize that, during the 30 days shown, Donnie comes to understand the reason for "Frank's" existence. For me, Donnie gave his life so he wouldn't die alone.
I loved everything about this movie. I recommend watching it at least twice.