Worked at IBM. Co-worker was in the datacenter, saw a bluescreened machine, and rebooted it. Much chaos ensued. Machine was part of a stability testing project, team running it was OTW to the DC to look at the machine, and were very confused when they arrived that it was running. "Helpful guy" was chastised, given a warning about touching machines that weren't his responsibility.
Two weeks later. Same guy. Same machine. Same bluescreen. Guess what he did? He rebooted it. Again.