Hitchcock famously described the difference between surprise and suspense. Say we're having an ordinary conversation and then a bomb explodes. That's surprising, but before that, the scene was rather uninteresting. Alternatively, you could show the audience the bomb being planted and that it's on a timer. Now the ordinary conversation is LOADED because we are participants; we want to tell the characters to get out of there! This is suspense. Hitchcock was an advocate for suspense.

Anyway, I'm in a library right now and I look over and see a semi-familiar sight: a man taking a nap. But then I notice what is on the ground next to him.

THIS. IS. SUSPENSEFUL.