We had a grocery shop at one time, my brother and I, and my father persuaded us to lend our HiAce van to a friend of his. The man returned it so badly dented that the side door no longer opened, then parked it outside the shop and posted the keys through the letterbox, without so much as a mention of the damage.
When we challenged him, he swore blind it was in perfect condition when he left it there, and that the damage must have occurred afterwards.
Yep that's exactly why I don't let anyone use my vehicles! That sort of thing infuriates me, people mistreating other people's stuff. It's bad enough that they do it, but then not to take ownership? Fucken assholes.