"I remember some years ago a pilot had the idea of pulling a CB to restore some engine instruments on a 767 and the RAT came out."
... and, more seriously, the DC10 (or was it a Tristar?) which suffered an engine separation when pilots thought it might be a good idea to see what happens if you cycle a breaker for one of the engine speed sensors in flight. Can't recall if all were killed in that accident. One wonders why these sort of things don't happen more often with "break power transfers" in flight after minor failures/glitches).
Of course, history is littered with "seemed like a good idea at the time" disasters... but if you're running out of choices.