And almost as fun as the time somebody managed to run something along the lines of
find . -print | xargs mv '{}' /tmp
in the customer's / - as root, of course. Ah the glad days before sudo.
That one didn't actually lose anything, which was worse than losing the lot with an rm -rf... because then it all had to be unpicked and returned. This was back in the days when a system could conceivably be moved into a /tmp filesystem and not run out of space. Not that that condition lasted for long ;-)
Y'know, you know it's been a long day when you start trying to parse ;-) as a command line argument...