An old lady went to the store to buy some food for her dog. Upon reaching the check-out, the clerk told her "I'm sorry ma'am, but the store manager heard that many old ladies on limited incomes buy dog food and eat it themselves. We now have a policy - if you want to buy dog food, you have to show us your dog." Annoyed, the lady went home, got her faithful Fido, and returned to the store, where they sold her the dog food without question. The next day, she returned to the store to buy cat food. Again, she's reproached by the cashier: "I'm sorry ma'am, but the store manager heard that many old ladies on limited incomes buy cat food and eat it themselves. We now have a policy - if you want to buy cat food, you have to show us your cat." Frustrated, the woman stormed home, retrieved her precious fluffy and returned to the store, where she was sold her cat food without further incident. The next day, the woman returned to the store and strode right up to the cashier with a box in her hand. "Put your hand in this box," she told the puzzled clerk. "What's in it?" the clerk asked. "Just put your hand in here," the lady said. "No, there's probably something in there that will bite me" "Nothing will bite you, I promise." Reluctantly, the clerk put her hand in the box, felt the contents, pulled them out to examine them and let out a scream. Smiling, the old lady asked "now, may I please buy some toilet paper?"