what is crazy?

i once owned a 1979 monte carlo. it was two tones of green; one ugly, the other hideously ugly. when i bought the car, the radio didn't work; neither did the horn. every other day or so, though, i would start the engine and turn on the radio to see if anything had changed. every time i got the same result - a dead radio. one day, however, i indulged in my usual habit of turning the dial to 'on' after starting the ignition and i heard static. after fiddling with the dials i picked up an oldies rock station and every day thereafter, the radio worked.
now this was no miracle. as it turns out, i had had a problem with a turn signal or the dashboard lights or something and had searched for the cause until i found two burned-out fuses. so i replaced them both. it was the day before the radio started working. the solution had simply been a burned-out fuse but i never would have realised the radio was now operational had i not habitually checked to see if would one day miraculously come to life. a few days later, i realised my horn was working, as well.

they say the textbook definition of insanity is 'repeating the same action while expecting different results'. this doesn't work for me. suppose a man walks into a dark room and flips the light switch and the light comes on. so he flips the switch the other way and walks out of the room. then he walks back in and flips the switch again. the light, of course, comes back on. now, suppose he repeats this action over and over and over and each time the light comes on when he flips the switch. by definition, for him to expect any other result is insanity. but what about the one time weeks later when he walks into the room and the light doesn't come on in response to the switch being flipped? obviously, we all know that the bulb has burned out but the result has still dramatically changed.
so my question is this: was the man sane after all? or is insanity sometimes correct?