I used to believe that the term "being mugged" meant someone beat someone else with a coffee mug.
A childhood belief about criminals

others believed things like this
- Bronski Beat - Beat Boy
"Meatball
Meatball
Hit that perfect meatball..."— Santa Puncher - I always thought the lyrics in I'm Blue were "I could beat up a guy"— Trisha Gaurav
- I used to believe that coffee was tea with milk in it.Anon
- I used to think it was illegal for children to drink coffee— C.W.
- I thought you could get toffee from mixing tea and coffee.Anon
- until 12 yo i thought buying and drinking coffee was illegal when you were under 18:) — smarty