Nothing

Once, late at night, an Englishman came out of his room into the corridor of a hotel and asked the servant to bring him a glass of water. The servant did as he was asked. The Englishman re-entered his room, but a few minutes later he came into the corridor again and once more asked the servant for a glass of water.

The servant brought him another glass of water. Every few minutes the Englishmen would come out of his room and repeat his request. After a half-hour the astonished servant decided to ask the Englishman what he was doing with the water. "Nothing," the Englishman answered imperturbably, "It's simply that my room is on fire."