When I was younger, a friend of mine told me that to be "mature" meant that you had a lot of friends, and being "immature" was like being a loser, geek, nerd, etc.
I went on for months calling people I didn't like "immature."
When I was about 10 I actually looked up "mature".
I still call people I don't like immature. and I know what it means.
A childhood belief about speaking

others believed things like this
- When I was younger I thought MTV was an x-rated station because I thought M stood for Mature.— Aeris
- I used to think that "cross-eyed" meant that people had X's for eyes, like dead people in cartoons.— Tim
- My friend's sister believed the lyrics to Gazza's "Fog on the Tyne" were "Fog on the dinasaurs mine all mine"— Suzanne
- When i was younger up untill i was like 8 or 9 i thought that famous people didnt poop only normal people!!!— kaitlin
- Someone told me People and fish went to the same place.I thought they meant humans get flushed— MrK
- I remember once a friend of mine told me that when ever you hold in your pee it would make your balls stronger— Zao