Here’s a cool true story from hackers of yore:
You don’t touch an unknown switch on a computer without knowing what it does, because you might crash the computer. The switch was labeled in a most unhelpful way. It had two positions, and scrawled in pencil on the metal switch body were the words ‘magic’ and ‘more magic’. The switch was in the ‘more magic’ position.
…
It was clear that this switch was someone’s idea of a silly joke. Convinced by our reasoning that the switch was inoperative, we flipped it. The computer instantly crashed.