These two guys, George and Harry, set out in a hot-air balloon to cross the Atlantic Ocean. After 37 hours in the air, George says, "Harry, we better lose some altitude so we can see where we are." Harry lets out some of the hot air in the balloon, and the balloon descends to below the cloud cover.
George says, "I still can't tell where we are, lets ask that guy on the ground." So, Harry yells down to the man, "Hey, could you tell us where we are?"
The man on the ground yells back "You're in a balloon, 100 feet up in the air."
George turns to Harry and says, "That man must be a lawyer."
Harry says, "How can you tell?"
George says, "Because the advice he gave us is 100% accurate, and totally useless."