Profit From Mistake
On his way out of church, Frank stopped at the door to speak to the minister. "Would it be right," he asked, "for a person to profit from the mistakes of another?" "Absolutely not!" replied the pastor. "In that case," said the young man, "I wonder if you'd consider returning the hundred dollars I paid you to marry my wife and me last July."
My friends and I were on a beer run and noticed that the cases were discounted 10%. Since it was a big party, we bought two cases. The cashier multiplied 2 times 10% and gave us a 20% discount.