I chop wood at the entrance to the Hall of the Dead. I know a lot about what goes on in there, but I never answer any questions unless I’m asked.
When the young lad comes out of the Hall, he’s carrying a magic hand-mill. Quite the treasure. It will grind out everything he wishes.
“Excuse me,” he says. “Once the hand-mill has started, can you tell me what to say to make it stop?”
Wise fellow. If you don’t know how to make the hand-mill stop grinding out your wishes, it will turn into your worst nightmare.
The Old Woodcutter in Why the Sea is Salt, Blue Fairy Book. Picture by Adolf von Menzel.