I went into the greasy spoon next to the office and ordered a Tuna On Wheat. The waiter said, "Oh, I'm sorry, we're out of wheat bread. You'll have to have it on white."
The next day I went to the same place and ordered the same tuna on wheat. Again he told me they were out of wheat, I'd have to get it on white.
The third time I went there I decided to skip the step of being refused the wheat and just ordered tuna on white.
The waiter looked up from his notepad and said, "Aren't you the guy who usually orders it on wheat?"