The patience of chess players

The stranger had been sitting between the two chess experts for four hours without saying a word or moving a muscle. At last one of the players could stand it no longer.

"Look here, mister," he said, "you've been watching us for four hours. Why don't you go some place and play a game yourself?"

"Can't," muttered the kibitzer without taking his eyes from the board, "I ain't got the patience."