Stinking Proof

One day, an old lady went to the store to get some food for her dog.

When she got to the counter to pay, the cashier said she needed proof that the old lady had a dog because some old people have been known to just eat the animal food themselves. So she went home got her puppy, bought it to the store and purchased the dog food.

One week later, she went to get some cat food. Once again the cashier needed proof that the old lady had a cat. So she went home, got her cat, came back and purchased the cat food.

Two weeks later, the old lady walked in the same market to buy something . She held a bag in front of the cashier and told him to put his fingers in the bag and then smell them. When the cashier did, he said, "It smells like poop!"

The old lady replied, "Can I buy some toilet paper now?"