When I was 5, I got a birthday card that had picture riddles. One of them featured a kiddie pool on top of a car. For several years I thought a "carpool" was literally a car that had a little pool, and I wondered why no one we knew had one...
A childhood belief about swimming pools

others believed things like this
- I used to think that a carpool was one of those bug, long limosine's with a pool all the way in the back.— Annie
- When I was a kid I used to think the "carpool lane" was an actual pool cars went swimming in— skeez
- I believed that the Kreepy Crawlie used to clean our pool, would follow me around the pool and eat me. — Mother-of-2
- I used to think that a "pool shark" was an actual shark that lived in a swimming poolAnon
- Whenever my fingers wrinkled from staying in the pool too long, I thought I was aging faster.— The Mortal Elf
- If you pee in a pool, the pee disappearsAnon