Is this tea or coffee?

Once a man was having breakfast in an English hotel. He look a drink from his cup and then said to the Waiter:
"Waiter, is this tea or coffee?"
"Can't you tell the difference, sir, by the taste?"
"No," said the man, "I can't."
"Well," said the waiter, "if you can't tell the difference, what does it matter which it is?