While part of a team of students at a hacking competition I was VNC'ed into an owned 2003 server, I was trying to get to the network settings properties menu, when my VNC session lagged and I clicked at the same time that my mouse reached the Disable interface.
Yeah ... I didn't live that one down, lost my team some points.
I've seen that done on live remote Windows servers at work - lag causing someone to hit disable on the network, causing someone to hit 'bridge' on the network card, causing someone to hit 'shutdown' instead of 'restart'.
One reason I really prefer text commands, as the sequence is preferred, so they can be typed and "queued" to execute in order when they arrive.
Yeah ... I didn't live that one down, lost my team some points.