Seen in uk.tech.digital-tv but I just had to share it with you. Written by Bill Wright. to whom all credit must go.
The teenage daughter at this house was in a strop because the water in her en-suite (!) was taking a while to run warm. The plumber tried to explain that there was quite a long pipe from the boiler to her private facility, and without listening at all she snarled "Look, is there some law or something that says I have to wait for hot water?" Quick as a flash the plumber said "Yes, it's one of the laws of thermodynamics, but I'll see if I can get it repealed for you." That plumber is my hero.
Peter Crosland