Peeping Tom

Vivian: What would frighten me to death? Set the mood for me, Mark.
Mark: Imagine… someone coming towards you… who wants to kill you… regardless of the consequences.
Vivian: A madman?
Mark: Yes. But he knows it - and you don’t.

One of Martin Scorsese’s favorite films, which just so happened to ruin the career of director Michael Powell (The Red Shoes). As noted in the Scream series, this was the first example of modern horror, being that it was the first time the audience saw the victims through the POV of the killer.