I usd to believe that at restaurants that had a BYO sign out the front, you had to "bring your own" meal.
A childhood belief about in the street

others believed things like this
- i used to believe that a sign in a cafe bone-fide meal meant meat with a bone in it— roy
- I thought for the longest time that a No Standing traffic sign meant no person should stand near that sign.— Shannon
- I used to think all Italians worked in pizza restaurants.Anon
- When I was a child, I used to believe that adding sugar would lower the over-salty taste of a meal.— Francois
- I always thought that duck sauce (from chinese restaurants) was duck poop.
— emily - My cousin thought ribs at restaurants were people ribs.Anon