When I was young, my sister told me that Stop Signs outlined in white were optional. I later realized that all Stop Signs were outlined in white and weren't optional!
A childhood belief about road signs

others believed things like this
- Having seen enough red octagonal STOP signs in my time, I used to look out for green circular GO signs.— Gary
- I Used To Believe That You Can Marry Your Sister Or Cousin As Optional!— KellGirl
- I used to believe that the sky had stop lights and road signs floating about for the airplanes.
— LoonaSM's - I used to think that Mice controlled the Stop lights and crosswalk signs.Anon
- When I was young, I used to belive that
if you pushed the stop button in the bus it would stop for good.— Tom (Norway) - I used to think that "No standing signs" meant that you weren't allowed to actually stand in the area!Anon