Just been discussing Brighton Rock's opening chapter, which for me is the ultimate in stomach-churning suspense. I can't think of anything better at making me freak out than that chapter. I've read all the various horror luminaries and they absolutely give me the creeps, sure, but Greene nailed it. Scarier on the first read because of not knowing Hale's connection to everything but either way, immense.
Which literature scares the merry fuck out of you?