"Well," said the director, "We fill up a bathtub, and we offer a teaspoon, a teacup, and a bucket to the patient and ask him to empty the bathtub."
"Oh, I understand," said the visitor. "A normal person would choose the bucket as it is larger than the spoon or the teacup."
"No," answered the director. "A normal person would pull the plug." Joke borrowed from http://www.retrojunkie.com/jokes/medical.htm