I know we've all done it. Our brother or sister or friend tells us something false, but we believe it for many years to come and then make a fool out of ourselves later on. I'm not sure about you guys, but I was told a lot of wrong things when I was young, and believed a lot of them.
For instance, I always thought marriage was the key to having children. If you weren't married, then you couldn't have kids. But if you were married, then kids would come out randomly until you were 40.
I also believed that gasoline (gas) was liquid "fart", and that I could run a car off of farts if I wanted. Stuff like that.
Let's hear your beliefs that you had in false things.