Psycho

It starts small. Rain on the windscreen, a wrong turn, a motel sign still lit though the road it once served has moved on. She only means to stay the night. The young man who runs the place is polite in a way that's almost too careful, quicker to talk about anything else than about the house on the hill behind him, where a lamp keeps being switched on and off.

This isn't a film that jumps out at you from behind a door. It lets an ordinary evening turn on you slowly, then spends the rest of its running time making you doubt your own reading of everyone in it. The dread sits under the skin rather than on the surface, and it stays there.

Watch it properly dark, properly quiet, with nobody talking over the parlour scenes near the end, because that's where it does its real work. It's a slow, careful kind of frightening, the sort that unsettles rather than jolts, and it lingers long after the credits.