How Much Do You Really Know?

A pedantic bore forced a conversation with a fellow passenger on a coast to coast flight, and made a great parade of his knowledge. The passenger listened as long as he could. Looking at him gravely, he said, "My friend, you and I know all that there is to know." "How is that?" asked the bore, pleased with what he thought was a complimentary association. "Well," began the traveler, "you know everything there is to know except that you are a bore, and I know that."