Here's a funny story our Christian counselor told my parents at one of their sessions...
One night, Satan decided to rise to the Earth to stir up some trouble; he found his way over to a nearby church that was in the middle of the Sunday night sermon. He bursts in and starts walking up and down the altar scaring people and chasing them off, he even managed to drive the pastor away once he made up front; he then turns around and sees one man still sitting in the altar, so he walks up to him and tries to scare him but the man didn't move, nor did he seemed to give a care. A confused Satan then said to the man "why aren't you scared? Don't you know who I am?" The man then replied "of course I do, I've been married to your sister for fifteen years!"