Basically you just say something that you used to think was correct, but was really wrong when you were younger.
Possibly a great way to embarrass yourself lol.
Examples: When I was young and stupid, I thought Africa was a country.
When I was young and stupid, I thought catwalks were walks for cats.
WIWYAS, I thought you got arrested if you edited Wikipedia.
I'll start.
WIWYAS, I thought US Marines and the Navy were all the same thing
