One of my customers recently fired an employee for poor performance and not showing up for work. As his "parting shot" to the company that gave him a job he wasn't competent to do, he switched off his computer, and then sneakily changed the voltage selector on the power supply at the back of the computer from 230V to 115V.
The next person who switched it on caused the power supply to burn out, frying the motherboard in the process. We're not sure if it killed the hard drive as well, but at least we have a backup of all of that stuff, such as it is. I'm very tempted to publish his name, but there are too many other people called
All I can say to the one who did it: we can't prove it was you, but since no one else in the office knew the consequences of doing such a thing, you just proved that you are a malicious jerk and a serious loser. I hope no one ever employes you in a responsible web design or IT job again, for their sake, not for yours. It will come back to bite you on the ass at some point in the future, I'm sure.