Not so much damage but I did have to put up with incompetence and outright thievery.
There was this time my metal band Slavantas got a roadie and boy did we EVER have our hands full with him.
- He'd run his hand across the knobs of my amp, screwing up my settings. When I confronted him he went "I see people do that all the time, isn't it common practice?"
- Another time, he had pulled my lead from my amp, which made it that when I started the first song of the set, I had no sound. When I asked who pulled my lead out, our roadie said that he did so, again because he saw everybody doing that and thought it was common practice. "But you COULD have told me before you did so!"
- I asked him to fetch my amp from my car and tossed him my keys. He walks out and comes back in without my amp. So I go "Where's my amp?" and he said "Oh, you mean that I had to bring it inside?" Eeyup, this numbskull took my amp out of my car and left it in the parking lot.
That guy knew poop from Shinola.
This was my very first amp which came in a beginner's package which I bought in 1988 on my 12'th birthday, a couple of years later I used it on my very first live performance.
Now the singer and me stayed close over the years until I started to see a couple of clues that he couldn't be trusted. I lend him a guitar and that little amp. And a few months later I got a call from him "Dude, I'm being evicted, I need your help getting my stuff away from my pad!" I told him, I couldn't because I was being hospitalized for surgery on my jaw that very same day.
A couple of weeks go by, I'm at home, fully recovered and he calls me "Dude, HOUSE WARMING PARTY! Will you be there?" So I go there, we're having a lot of fun and out of the blue he goes "Oh and by the way, can you lend me an amp?" and me going "What for, you HAVE an amp of mine!" at which he got all shifty and admitted that it got "left behind" at his old adress.
Fast forward another couple of months and once again he tells me he's being evicted. With no hospital date, I decided to help him out but as I'm loading all his stuff into my car I notice my guitar is nowhere to be found, I asked him about it and he goes "Ah don't worry it's at my parents' house." Thinking nothing of it, I let it slide.
Fast forward a couple of weeks and he goes "Can I borrow a guitar?" at which I go "What are you talking about, you have one of my guitars!" and he begins some BS story about how it went to somebody else but this time I'm not buying it "Dude, if you lost that one, I demand you pay for it!" and he goes that he can't and how I have no idea how much it cost to keep a family provided for. I told him that that was besides the point, he cost me damage and needed to pay for it. I never saw that guitar again.
A few years later, I'm at a party and he goes "Would you mind lending me a guitar?" and I go "Yes unless you intend to buy it from me." at which comes the speech of "You don't know how much it costs to keep a family provided for." at which I point to his then brand spanking new Playstation 3 and go "Okay, mind if you tell me how you could afford THAT?"
Five years ago this month, I was hospitalized once again with a destroyed shoulder and he calls me up and goes "Dude, can you believe that we've been best friends for 30 years this year?" at which I went "Yeah we would have been if I hadn't stopped trusting you 15 years ago!"
Never once did he man up and told me what REALLY happened to that equipment I lend him, nor did I EVER see a cent of compensation for the damage he cost.