Things you only do ONCE!

[yash101]

That is true. BTW, let me say, that was before my first safety lesson. Thankfully I didn't hurt myself, but now I drill with a vise or a clamp. Also, I typically use a drill press because even though it has a stronger motor, it seems safer because the bit is less likely to move and cut a finger off.

So back onto the topic:
don't touch both terminals of the battery, especially if it is raining and you just came in, wet!
Don't touch spinning motors. Those BAGs may seem tiny but they pack some force and some speed for their size. Even worse, don't touch those old-and-trusty CIMs!
Don't touch a robot if it is on and enabled. You don't know when something can go awry and the next thing you know is the robot is pushing full-force towards you, likely to hurt you! Always disable and/or shut down the bot before doing things.