Never loan money to friends.

If you loan money to a friend, you will lose your friend as well as your money. Give them whatever you feel like giving. Then forget it. Ditto with relatives. If you diligently follow this one piece of advice, you will be saved a sackful of misery. Trust me. Broadcast your policy loudly. This will spare you from many embarassing demands that will otherwise vex you.

-How to get rich, p.276