Ha, don't worry, anybody who works with such things that says they have never done something like that is almost certainly lying. We have a "wall of flame" in one of the cubicles where I work to hang such things. My favorite addition was when someone we were helping design some boards for an Electric Vehicle somehow accidentally wired the full battery stack voltage directly to the microcontroller on one of the early prototype boards. There was literally a more or less perfect square hole the size of the IC burned through the board (along with some other components that exploded fantastically). I'm sure he got a long laugh out of the incident after he cleaned the mess out of his pants, he did send us the board back as a trophy after all. :-)

I've accidentally welded a component to a circuit board once (and subsequently tripped one of the main breakers in the lab to make the other engineers very angry about interrupting their running tests) when I was working with a mixed high-voltage AC and low voltage DC board. I never did figure that one out. I was isolated through a variac, and the variac box was right next to me when it happened, and it let out a frighteningly loud 60Hz buzzing noise that nearly made me mess myself... Ah, good times, but I'd prefer to never go near anything higher voltage than a non-electric car battery ever again.