American History X
It's incredible when you consider American History X was the first feature film for both its director and screenwriter.
It's a violent story, not only in the obvious physical violence (explicit and implied) but it's intellectually violent in the portrayal of a racist, hate-filled worldview.
Edward Norton's Derek character pre- and post-prison sentence are almost two different characters, and the way this story is put together shows you how he became both of those people.
Scariest scene is the flashback to Derek's father, inculcating his sons with racism of the head. It all starts in the head before it works its way to the fist.
For an American film about America with America in the title, it's puzzling that this film made over 70% of its income overseas. What does that say of America?