Proof required.

A man shopping in a supermarket brought his purchase of two cans of
dog food to the checkout counter. The cashier asked, "Sir, do you have
a dog?"


"Yes." the man replied.

"Well, where is it?" asked the cashier.

"I left him home." he answered.

"Sorry," the cashier said, "You can't buy the dog food if I can't see
the dog. Those are the rules."


The next day he returned to the store and brought some cat food to the
checkout. "Do you have a cat?" asked the cashier. "Yes," he said, "but
I left him home."

"Sorry," she said, "If I can't see the cat, I can't sell you the food.
That's the rules."

The next day the man walked into the store with a brown paper bag. He
walked up to the cashier and said, "Here. Put your hand in here."

The cashier put her hand in and said, "It's soft and warm. What is
it?"

The man replied, "I'd like three rolls of toilet paper!"