When I was little I used to believe that the blank pages at the end of the book were for writing a different ending if you didn't like the original ending to a book.
A childhood belief about reading

others believed things like this
- I thought that there was a law that all movies had to have a happy ending— Quatsch
- I used to think Russians had surnames ending with ski because of the skiing they do in Siberia.Anon
- I used to believe if you read a book in the dark, you would go blind.— Ellen
- I believed the book Babar was how my name was spelled.— Barbara
- i thought that we were just a big story book that ended when we died— samantha
- I used to believe that copying definitions out of a book counted as plagiarism!Anon