I was convinced for years that the ohio express record 'yummee' went 'yummee yummee yummee, i've got bugs in my tummy'. It wasn't until I was about 35 that I realised my error.
A childhood belief about misheard lyrics

others believed things like this
- I used to think a world record was a record of all the people in the world singing .— JACK REGAN . [SWEENEY . ]
- There was a Chinese takeaway near us called the Orient Express. I thought it was Onion Press. Yeah.— Spook
- I believed that lightning bugs were faeries....
::sigh:: I miss those enchanted years of my youth.— Andrea Sorenson - I used to believe that you could only play a record once, and after that all the sound was wiped off.Anon
- I used to believe that if you played a record too many times it would wear it out.— April
- I used to believe that records were the power source for record players.— bob