It makes you a suicidal person. http://en.wikipedia.org/wiki/Superheating
I've had the relays melt closed and blow the breaker on a MW oven that had distilled water used to make coffee and was forgotten and reheated which caused superheating and a explosion of steam. The mw door has 2 safety switches, the deeper one keeps the power to the magnetron on when the latch/door is closed and the latch tip sits on this switch, the 2nd switch (closer to you in the latch hole) is briefly toggled as you pull the door open, grounds the magnetron power input. Normally the deeper switch already disconnected before the shallower one is briefly toggled as the door latch is pulled out or pushed in, but because of the steam explosion the door flew open so fast the deep switch didn't lift fast enough before the shallow switch closed and the breaker blew. The shallower switch is a safety mechanism if the deeper switch was stuck and the door was opened. I had to replace a relay on its control board and did a radiation test on the mw oven and its back in service uneventfully.