On a much smaller scale but I did shut down the wrong database application server once. There was a treeview where you'd select an instance to control with start/stop icons located on the main menu bar. I didn't notice the focus had shifted from test to live before I clicked that stop icon. Almost immediately, I heard a wave of groans rise and pass thru the entire building. If I remember nobody really asked what had gone wrong and after about fifteen minutes I was actually a hero for getting things back up and running.
That old application server is still running today, the only difference now is that I double (or even triple) check status before I click on anything.