As a child, the tale of Little Red Riding Hood had me convinced that wolves were quite large enough to swallow Little Red Riding Hood and her grandmother whole, even if they were quite unlikely to actually do so. So I envisioned wolves as huge. Then I was very disappointed the fitst time I saw actual wolves (in a zoo) and saw they are no bigger than some of the good-sized breeds of domestic dogs.
A childhood belief about general

others believed things like this
- Wolves lived under my bed when I was a kid.— ricolarno
- I used to think "Robin Hood and his merry men" was "Robin Hood and his *married* men."Anon
- I used to believe "mixed breeds" of dogs were made by two dogs being put in a blender— Andie
- i thought hot dogs were made from real dogs and sum tasted good sum didnt.— Wayne
- i used to think my grandmother's actual name was Gramma!— el kristadore!
- Since lions and tigers are larger versions of cats, I used to believe bears were large dogs— Chris Ayala