I have one of those battery-powered Colgate Pulsar electric toothbrushes.
It's the best.
Lately the brush has been acting up, I'm sure the battery is slowly dying or something.
On two different mornings this week, I have rinsed off the brush, loaded it with toothpaste, set it against my two front teeth, switched on the power button only to find nothing happens, and thought to myself "Crap. Now I can't brush my teeth."
...until I remember that MY ARM STILL WORKS.
Just had to tell someone.