Normally this arrangement is very stable, but it can move, and if it does, you're fucked. So I'm up on stage, and I'm opening the evening (for bonus points, I guess), and I play Stars better than the last open mic if not up to my standards, I'm starting to get some control over the singing-and-playing fear, and they seem to like it. I have some reasonably amusing banter with the crowd, which was fun, and went into Thought You Knew, and in... I think the second verse? I don't even remember how far I got... I touched the bridge while playing, and it made this pink noise and suddenly my mandolin was unplayable. And I had to get off stage, because you can't fix this quickly; basically the two lowest strings were a semitone flat, the upper two strings were a semitone sharp, and the strings in the middle were all just various degrees of wrong. So that's malfunction nr. 1.
Now, the MC said I could come back up after a few other acts, which was great. But to really properly fix this, you need to de-string, reset the bridge, and re-string. I didn't have time to do that (...or so I thought...) so tried to reset the bridge without destringing, which can work, but you don't want to trust it. But this open mic only gives you two songs anyway, so I thought, okay, maybe it'll hold up for one song. Now, what's annoying about this is that I didn't think I had any other options, just because of the time involved - but as my second-time-up kept being delayed until later in the night, it turns out I would've. But at no point was I being told "You have an hour," I was mostly being told "three or four other people, then you."
So eventually I do get back up on stage (three and a half hours later - I opened the thing, I damn near closed it, but somebody else signed up to keep it going) and I have a little more fun banter with the crowd and then I start again... and I don't even get through the chorus when it goes PANG and this time it's loud enough that the sound guy flinches, and this time it's even worse, and I'm just doomed, and the performance gods go HA HA FUXX0R J00 and I get off stage and leave and then pound on the steering wheel of our car for a little while out of frustration. And that was nr. 2. And I was so mad I cried a little before I could drive home and spazzkat says I'm still "steaming" about it.
So now you know.