I used to think the conductors wand (is that what its called?) made all the music. So I was sitting at my sisters concert with my dad and I kept saying "whats that thing the ladies waving, and how does the music come out of it?" and he said "thats the (something, I forgot what he said) and it makes a variety of noises". I didn't realize 'til a couple years later that he was just messing with me.
I used to think people were unable to hear people when the louder they yelled, because when the vacuum cleaner would be on and I would scream my mom would say she couldn't hear me.