Whats the scariest moment in a horror film you have even seen?

I agree with Exorcist 1 and the spider walk but I was just as freaked out when she comes down the stairs during her parent's party and pees on the floor. The scariest moment for me, though, would have to be when the little boy is riding his Big Wheel in The Shining and he comes around the corner to see those 2 dead girls standing there. Even at 31 years old that freaks me out.