Daily Quote: "Discord occasions a momentary distress to the ear, which remains unsatisfied, and even uneasy, until it hears something better."
(Burney, Charles -
Unity)
A joke is not a thing but a process, a trick you play on the listener's mind. You start him off toward a plausible goal, and then by a sudden twist you land him nowhere at all or just where he didn't expect to go.