i used to believe that if you laughed too hard you would run out of air and die and that's why you were out of breath after laughing very hard. you had just had a near death experience!
A childhood belief about general

others believed things like this
- I used to believe if you fart hard enough you can fly— Bob
- i used to think that i would become a fairy if i just wished hard enough!!!LOLAnon
- I used to think croutons were hard chicken. Anon
- I used to believe that if I threw up too hard my brain would explode.— Tammy
- that if I flapped my arms hard enough, I could get airborne.— DeQuendre
- I used to believe if I concentrated hard enough I could move stuff.
*sigh*
— Zog