When I first heard American Pie, I misheard the chorus as "buy, buy me some 'Merican pie". I didn't know why Don McLean couldn't just buy the pie himself.
I used to believe that yodeling was illegal in certain countries.
I used to believe "I Want Candy" was actually "I'm A Kidney", especially since they played it in PE/health class at my school.
When I was in Grammer school we sang a Polish folk song about how the "Vistula" ( a river in Poland) was flowing. I misunderstood and thought it was "fistula" for years.. Then someone told me a fistula was a boil you get on your rear end. Talk about embarrassed...
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.
I used to think bands or singers could be sued for plagiarism if they coincidentally had a song that was too similar to one by another artist, but not as a cover!
At one point, I believed that Lauren Mayberry was future me, but I'd got a hold of a time machine, and came back to the time when I was the age I believed this.
I think that I thought that Fergie from The Black Eyed Peas was Gloria from Madagascar.
I always thought that Beyonce's 'All The Single Ladies' was about drawing circles around the toys you liked in the catalogue. It didn't help that my parents called the action of drawing a circle around an image in a catalogue 'ringing'.
"If you liked it, then you should have put a ring on it"
When I was little, when the band Years And Years emerged, I thought that the radio said that they were playing a song from 'years and years [ago]'. Being a kid who only liked new songs, I would switch over whenever they'd play. When I heard 'King' on the radio regularly though, I was surprised because I thought it was an old song.