When I was younger, I always thought (for some reason) that when the sign for a service station said 'Not 24 hours', it meant that it didn't take 24 hours to get there (and the ones that didn't say that did take 24 hours to get there, I suppose).
One day while I was in the car with my Dad, I pointed it out to him, and he asked me if I knew what it meant. I said yes, so he asked me what, and I was about to say what I thought, when I suddenly realised it meant that the service stations weren't open 24 hours.
So I quickly said that, and never told him what I really believed.
A childhood belief about in the street

others believed things like this
- In kindergarden my friend told me that there were 24 hours in the day and 15 hours in the night.— Cari
- I thought that days had 100 hours in them. Very surprised to hear there were only 24.— Cassiopeia
- I believed that if I swallowed my phlegm I would die. I spent hours spitting it out into the toilet.— chunky munky
- I thought that the "don't walk" sign at crosswalks meant to run across the street as quickly as possible!— richard
- i used to believe you slept for 100 hours every night.— skye-ness
- I used to believe that i swam more than 2 hours I would become a mermaid.— M11cazares