I lent out my new strat (guitar) to a friend for a mere 5 minutes. However, I didn't notice that the jacket he was wearing had zippers facing outwards. After playing it for a few minutes he gave it back and this happened.

I can probably take it to a GC Repair center and get it fixed, but it's a pain in the ass.
Lessons:
Don't let freinds use expensive things
Satin finishes are more fragile than glass