It's wrong not to be fair to others.
Lisa collects money from all of her friends to buy concert tickets to an upcoming show, but one friend gives her too much money.
Lisa needs to decide whether to refund the excess money that her friend gave her.
Lisa refunds the extra money to her friend, when she gives her the ticket to the show.
Lisa pockets the extra money that her friend had given her, never mentioning that she hadn't spent it on the ticket.
Her friend thanks her for catching the mistake and Lisa feels like a good friend.
Lisa's friend finds out that the tickets were less expensive than she thought and confronts Lisa, Lisa is ashamed and her friend is angry.