After classical violinist Fritz Kreisler was invited to a society party, the hostess urged, "Of course, you'll bring your violin."

"In that case," Kreisler said, "my performing fee is two thousand dollars."

Insulted (or caught out), the woman huffed, "In that case, I shall ask you not to mingle with my guests."

"In that case," Kreisler replied, "my fee will only be one thousand dollars."