When I was little I seen a commercial on TV that talked about how your lungs turned black when you smoked. After hearing this I was horrified whenever my parents or grandpa would light up in front of me, to the point where I became hysterical because I somehow convinced myself I could "see" their lungs turning black.
A childhood belief about smoking

others believed things like this
- I used to believe that the lungs where tubes in the neck.— Some Guy
- All through life, I always thought the lungs were located in your throat. I'm 25.— thelungs,man
- When I was i kid I used to believe that if i strained too hard while doin #2 I would poop my lungs out...— K.Gordon
- When I was young I used to believe for some reason that being asthmatic meant you were born with no lungs.Anon
- My sister told me once that if I sucked too much helium out of a balloon, my lungs would explode.Anon
- My older brother told me that everytime you sneezed your lungs would bleed. I believed this until I was 21!— Gem