2645: You hear your friend/parent/roommate/fiance walk in the house whil you're playing Thief. In an effort to play surprise on them, you try to hide but you're only hiding in the game - you're running around a room [in the game], dousing torches and shutting off lights. You think you've found a hiding place, and you wait for them to walk through the door that you've doused the surrounding torches around...You wait, and meanwhile, IRL, they're standing behind you wondering what you're doing. When they tap you on your shoulder, you freak out.
I don't know if anyone can relate to this, but I've done it so many times in so many 1st-person games.