A person checks into a hotel for the first time in his life, and goes up to his room. Five minutes later he calls the desk: "You've given me a room with no exit! How do I leave?" The desk clerk says: "Sir, that's absurd. Have you looked for the door?" The client answers: " Well, there's one door that leads to the bathroom. There's a second door that goes into the closet. And there's a third door I haven't tried, cause it has a 'do not disturb' sign on it."