The Shining
Terrifying, it's as simple as that.
The entire movie feels like you're zoned out with ringing in your ears while some amazing performances happen by Jack Nicholson and Shelley Duval. I wasn't sure about Duvall at the beginning, but as the movie progressed, I was completely on board with it. Lloyd did a pretty good job for being a rather inexperienced child actor.
There are countless analyses about The Shining about its themes of potentially and not exclusively, Racism, sexism, Masculinity, Oedipal complex, Faustian dealing, psychological torment, Native American tension and history, American imperialism, cabin fever and mystique. THAT'S A LOT, and I don't have it in me to research all of this and how it is portrayed in the movie.
King notoriously dislikes this movie, but I think he is just the purest sensibilities about his book. This is a fantastic horror that you must watch.