Dutch radio DJ Jeroen van Inkel confessed he used to think it was:
"I got my first real sexdream"
instead of
"I got my first real sixstring"
(Bryan Adams - Summer of '69)
I thought is was sixstream, but hey, I'm dutch!
A childhood belief about misheard lyrics

others believed things like this
- I used to think that all Dutch people wore clogs and lived in windmills— American
- i used to believe dragon ball z was real
and namek was in another dimension
and every show on tv was realAnon - I used to believe that boys were like robots and had no real feelings, that they were not even real people.— Lisa
- i used to believe that the telly tubbies were real because the rabbits are real!!— hotty
- the beatles song 'mean mr mustard' says "shes a real go-getter", i was sure it was "shes a real coconut"...— sally
- the summer that I turned 11 I waited out side on the step all summer for my hogwarts letter... ;D — Ginny weasley... not really