I went to a gas station and gave the attendant $20 to refill my tank. He mistakenly put in more than $20 worth of gas. Should I have insisted on paying only $20 or paid the difference?
—Vincent Mazzolla, North Arlington, New Jersey

Technically you can refuse to compromise. You made a clear verbal agreement, and one party failed to fulfill his side of the bargain. If you insisted on not giving the station one penny more than $20, there’s not much they could do. But is that something you ought to do? I don’t think so. The man made a mistake. It’s not as if he accidentally filled your car with diesel fuel or poured a cup of sugar into the tank. The extra gas will ultimately be used by you in your own car. In a perfect world, the attendant should have offered the extra fuel for free, because this was his error. But as an employee, he may not be in a position to do so. Just pay him the extra bucks and move on.
—Adapted from “The Ethicist” in The New York Times Magazine