Mercury and The Tradesmen

When Jupiter was creating man, he told Mercury to make an infusion of lies, and to add a little of it to the other ingredients which went to the making of the Tradesmen. Mercury did so, and introduced an equal amount into each in turn: the tallow-chandler, and the greengrocer, and the haberdasher, and all. Until he came to the horse-dealer, who was last on the list.

When, finding that he had a quantity of the infusion still left, he put it all into him. This is why all Tradesmen lie more or less, but they none of them lie like a horse-dealer.

Deception is often considered a natural part of commerce.