Many years ago, on a Center frequency, this conversation was heard between ATC and a British Airways 747 decending through FL200 for an approach to San Francisco.Oakland Center: BOAC 313, could you expedite your descent to cross Faith intersection at 10,000 feet and 250 knots?BOAC 313: I believe so, old chap, but I won't be able to bring the aircraft with me.Bob

Yeah, I've had days like that. ;-)