Ever been to one of those parties where a creepy pale guy comes up to you and says he is in your house right now?
Creepy homeless person behind diner [the way in which the tension gets ramped up in this scene is incredible, I remember being shook by this scene when I first saw it, since it doesn't fit in with the rest of the movie at all, it's like Lynch paying homage to Kafka here, or something, it's just nightmarish and bizarre]:
Taxi Driver - the climax:
Jacob's Ladder:
It's not on Youtube (due to copyright nazis) but it's the scene where Jacob is just minding his own business walking down a side road and then all of a sudden a car comes speeding around the corner and tries to kill him, he just manages to escape in time by diving into the side of the road and looks at the car, noticing this creepy demonic head looking right at him in slow-mo as it drives past and then he gets up and looks at the car and there's this bobbing head that's looking at him through the back window that looks like its decapitated, or something. That scene just gave me the chills when I saw it the first time. Crazy and unsettling. Everybody always talks about the train scene or the hospital scene, but that scene creeped me out the most.