It happened once upon a time that Mullah Nasruddin went into a clothing shop, with the thought of buying a pair of trousers. He browsed through what the merchant had, held a pair against himself and looked in the mirror, but then decided he would rather buy a jacket.
Carefully replacing the trousers, he found a jacket he liked, put it on, studied himself in the mirror, and then, satisfied, started out of the shop.
“Mullah, wait!” shouted the shopkeeper. “You haven’t paid for the jacket!”
“No,” said Nasruddin, “but I gave you the trousers. They are the same price.”
“But – ” said the merchant in confusion, “you haven’t paid for the trousers, either.”
“Certainly not,” said the Mullah. “You don’t expect me to pay for what I don’t want, do you?”