I went a whole year in my apt. never using the oven because i didn't own an oven tray. I got a gift card to target on christmas so i bought an oven pan there. So i baked some chicken and pizza rolls. after which i turned the oven temp down to zero thinking that was how i turned it off. Even though to turn it on i used the on/off knob, which at that point I totally forgot existed. so over the course of two weeks my oven was left on, the elements popping on and off every few minutes and i couldn't figure out why. my conclusion was that there was an issue with a fuse in my fuse box. before i got that far though, i suddenly noticed the on/off knob on the other side of the oven panel...
that was the dumbest thing i've ever done in my life, normally me electric bill was $40 a mo. that month it was $160. longest brain fart ever.