We received a phone call late one night from an old school-friend of dh's who had fallen on hard times (well, had fallen into "bad company" and was pretty debilitated from drugs and alcohol), asking to borrow a relatively small (to us) amount of money to put in his electricity meter. He said he had no one else to ask (reasonably affluent parents had I think given up on him). He promised he would pay the money back by Friday.
It seemed an odd amount to ask for, and a sign of his desperation that he would phone up dh after not having been in contact for some time. Dh dithered for a short while wondering if the money would be spent on drugs and we of course know that you should never lend money unless you're aware that you may not ever see it back. That wasn't the issue.
Dh said he would of course lend, but that if friend didn't repay it, to please not ask again. We expected that it would be a gift really,
The following Friday, he turned up at the door and handed dh the money back. 
As a total aside, his remaining parent died recently, and the house was up for sale at nearly £3/4 million. I'm wondering how he will manage his inheritance. Last we heard, he had cleaned up his act. I really hope so.