Wow. And I get scared when I play Portal at night. Polar opposites.

Are you allowed to post a link to System Shock here?

There is one incident that I remember, but I can't remember what game it's from. You go upstairs into a hallway, with three or four doors on either side. Knocking begins on the other side of one of the doors, about 3/4 of the way down the hall. As you approach the door, the knocking becomes more and more frantic, until you reach the door and fling it open to reveal-

(SPOILER)-nothing. There is no one in the room and no other exits.

Good God almighty.