A little old lady went to the grocery store to buy cat food. She picked up three cans and took them to the check out counter.

The girl at the cash register said, "I'm sorry, but we cannot sell you cat food without proof that you have a cat.  A lot of old people buy cat food to eat, and the management wants proof that you are buying the cat food for your cat."

The little old lady went home, picked up her cat and brought it back to the store.

They sold her the cat food.

The next day, she tried to buy two cans of dog food.

Again, the cashier said, "I'm sorry, but we cannot sell you dog food without proof that you have a dog.  A lot of old people buy dog food to eat, but the management wants proof that you are buying the dog food for your dog."

So she went home and brought in her dog.

She then was able to buy the dog food.

The next day she brought in a box with a hole in the lid.

The little old lady asked the cashier to stick her finger in the hole. 
The cashier said, "No, you might have a snake in there."
The little old lady assured her that there was nothing in the box that would harm her.

So the cashier put her finger into the box and quickly pulled it out.

She said to the little old lady, "That smells like crap."

The little old lady said, "It is. I want to buy three rolls of toilet paper."

Don't mess with old people