I used to hate that song about the Weeping Willow "crying on his pillow" because I thought it was an actual guy as opposed to a tree, and thought it was too sad. Then, I learnt that Willow was a girl's name and thought that maybe the man was actually named William.
A childhood belief about songs

others believed things like this
- I used to believe that the Doller Tree store was an actual tree.Anon
- I used to think that partridge in a pear tree was "cartridge" in a pear tree(christmas song)— Erica
- Until I was about eight I thought that there had been actual fighting during the Cold War.— Miss Taken
- I thought that smoking pot involved an actual pot from the kitchen.— Aeris
- My sister thought (not more than one year ago, she is now 14) that John Doe was an actual person.— Brother to Natascha
- I thought baby back ribs were from actual babiesAnon