Scariest movie you have ever seen . . .
The Grudge, The Exorcist, Ju-on, and most recently Insidious make the list but I'll say The Shining is still the scariest.
I think part of the reason this stuck with us so much is that we had a brief membership to HBO or The Movie Channel when this was making it's way onto cable. I remember I had to leave the room with this would play.