Oh man, too many to list. So many times when I'd be in a band with a PA, and we'd say "Hey other bands - if you use our PA, please try to put the settings back to where we left them, ok?" only to find it cranked straight to hell when we'd come in to practice.
But by far, the worst was the band I shared a space with back in college. You couldn't leave your instruments in the space, because when you did, you'd come back to find broken strings and missing guitars straps. Once, a friend opened his guitar case to find every string on his guitar broken and blood all over the pickguard. Plus they'd leave empty beer cans and booze bottles around (like the place didn't smell bad enough already).
And then one of them left the window open over winter break, so the pipes froze and burst, flooding the space...
And THEN there was the time one of them wanted to jam with some friends (drunk), but had forgotten his keys in his dorm room... so he kicked in the door... which I discovered hanging from the hinges the next day when I went to practice... and I knew who it was, because when I called the guy to ask what happened, he described the whole thing, and apologized for not telling me sooner...
Let's not even go into rent collection... I hated being "the responsible one" who'd have to hound people for their share...
