I used to think that a sign saying "Dead slow" meant that you had to drive fast. I thought that the sign was asking you to act as if slowness was dead or didn't exist, i.e. drive fast!
A childhood belief about road signs

others believed things like this
- I used to believe that a street sign that read "Dead End" meant that there were dead people buried there.Anon
- I used to believe a dead end sign meant there was a graveyard at the end of the street or zombies — Still Out There
- I thought the no overtaking sign meant that red cars cannot drive by black cars.— Helen
- i always thought that a DEAD END sign
as where they put all the road kill.
— pav - I thought for the longest time that a No Standing traffic sign meant no person should stand near that sign.— Shannon
- I thought that the sign "!" meant: "look at the wonderful landscape"— Giorgos