When I was a kid, I was scared of the lady who worked the drive-through at the bank because her voice was robotic and metallic-sounding. I thought it was her normal voice, but as I got older I realized that the intercom system changed the sound of her voice.
When I was a kid, I assumed that the school bus that I rode every day to school had accordion-style hinges in the middle, to help it go around sharp corners more easily. I always wondered where they were hidden, because I never saw them.
When I was a kid, I thought that cordless phones weren't truly cordless, that they had really long invisible cords that attached to the base. I thought that this invisible cord was so thin that I couldn't feel it if I tried to hold onto it.
When I was a kid, I thought that construction crews painted the yellow lines on the road with paintbrushes. When the road I lived on got re-paved one summer, I was sorely disappointed to find out that the lines are spray-painted.
When I was a kid, I thought that the automatic doors at the grocery store were controlled by someone pushing and pulling different levers to make them open and close. I always saw people waving at the top of the doors whenever they wouldn't open, and then finally they would.
What things did you learn as you got older that disproved your thoughts as a child?