You can pay the barber, but you can't buy him breakfast.

17th century idiom.

A formal deductive logical device used in a debate that simultaneously agrees and disagrees with any proceeding statement or argument.

See also "It's a dog-eat-dog world, Winston Churchill said that."

A: Al you old son of a bitch, how you doing? how you feel about the Dolphins? That call last night was aweful.

B: As far as I see it, you can pay the barber, but you can't buy him breakfast.