For the first 18 years of my life, I thought it was odd that the one thing it was illegal for me to sell or trade was my bathroom weigh scale. What kind of controlled device was it that it couldn't be sold to someone else or traded for something else?
And yet, every one I've ever seen had that label clearly displayed: "Not for Sale or Trade".
It wasn't until I mentioned it out loud that a friend pointed out (amid laughter) that the scale could not be used to *weigh* things for the purpose of pricing them.
A childhood belief about bathrooms

others believed things like this
- When I was around 4 or 5 I was convinced that you would weigh less if you sucked in your stomach on the scale.— S
- "Somewhere over the rainbow
Weigh a pie."
Why did Dorothy weigh a pie somewhere over the rainbow?— John - I thought drug stores sold drugs. I never understood how they could sell illegal drugs.— Diana Rios
- I used to believe that drug stores sold illegal drugs and I couldn't work out how they got away with it.— Bigg Jase
- I used to think that Legal and Illegal meant the same thing (illegal)— Dhruv
- When I saw signs stating "Lots for sale" I thought it meant that there was a lot for sale.— Robin