OK your stories beat mine, but I don't get paid to do this, and this was just last night . . .
OK, so like I said, I just do volunteer stuff, which always substandard gear, which is normally OK, I can deal with it. At this particular venue, they had a 20 ch Mackie board, rack of Crown amps, hardwired mic jacks and monitor sends, thought this would be the best gig ever. At the first rehearsal I learn that most of the mic jacks don't work, and the Mackie is in a totally impractical location for mixing. OK, no problem, I bring my lowly 12 ch board instead and find a couple of functional plugs to sub into the Mackie. Also I should mention that most of the abundant power outlets don't work which is scary as hell, but I only need one so I don't care. First rehearsal goes fine.
Second rehearsal is good, I am loving life because by now I've had like 5 hours of soundcheck and things sound good. Unfortunately near the end, the monitors go out, which I eventually diagnose to the monitor send outlet (big surprise).
So for the show I bring a fresh jack and my soldering iron and swap out the old one, monitors are working fine. In the meantime I do a couple of dumbass things like leaving my mic case at home (the spouse brought in time) that increase my stress level but don't hurt otherwise.
So then like 5 min to curtain the monitors let go again, I pull the recording guy to help with the problem. Both of us are laying on our guts hardwiring the monitor cable into the wall as the new jack I brought also doesn't seem to work. 10 mins late, we get it working, I bring up the levels, everything is OK, then like 2 mins later, hideous violently loud feedback runs through the monitors. Still don't know why that happened, but it was OK from there. Sounded good actually. After all, I had 5 hours of soundcheck . . . it's 15 hours later and I still want to cry. . . it'll be a long time before I use a system I don't know again!