Whenever I saw a sign that said "Not a Through Street", I thought it meant the street was still under construction. They weren't "through" building.
I also confused through and thorough.
A childhood belief about road signs

others believed things like this
- I thought that the "don't walk" sign at crosswalks meant to run across the street as quickly as possible!— richard
- my mom believed when she was little that a street sign that said don't walk meant you better run.— Sara Mclen
- 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 used to believe that a street sign that read "Dead End" meant that there were dead people buried there.Anon
- i used to believe that the no outlet signs meant that noone in that section of the street had electricityAnon
- when I saw a sign with a deer on it I always thought deer had to cross the street by it. like a cross walk— only me