My overall history of employment hasn't been bad, really; nothing to scoff at, but one time while working consumer I.T. (I still do from time to time), on particular job I took on was just utterly disgusting. I had to 'fix' this guy's laptop, and it started off bad, because he couldn't coherently describe the problem with the laptop, so I had no clue if it was hardware or software to begin with...
...but I took it and figured I'd see what I could diagnose. It was bad from the beginning...and pretty straightforward what was wrong with this guy's laptop. Let's just say he visit particular websites, that are meant for adults and can conjure up a physical reaction in people - and he was one of them...and that 'reaction' was all over the computer, literally making it near impossible to open the laptop, and generally made seeing the screen difficult. I wish I had a HAZMAT suit that day.
I recovered what 'clean' data I could (Ohhh, the IRONY!), and basically told the guy he needed a new laptop, which really, he did.