I once lent a friend at school my copy of Star Wars: Demolition for PS1. Critically panned, looking back, but I loved it! ... Got it back a couple of weeks later and the disk was snapped in half. Devastated.
Parents got involved, and he eventually (and reluctantly) had to give me one of his games as compensation. He gave me Mission: Impossible, disk only, no manual. Terrible game. I'm still annoyed.
I let a friend borrow my copy of Conker: Live and Reloaded years ago. Somehow, while on his desk, he managed to snap it in half. When I asked for it back he found it underneath something, went "oh shit.. sorry bud" and handed it back. Dude was like 3 times my size and I hate confrontation, so there went that I guess lol. Never compensated me for it or anything. Last time I looked it up it's kinda rare (lol) to find these days.