There's a scene in Mary Poppins, where Mary's uncle is floating in the air laughing, then when the others laugh, they also float. Mary and Bert describe the uncle as "contagious", so my cousin and I thought that he had some sort of disease that made him float. We called it "the float-when-you-laugh disease".
When I was little I did not know that when you throw up you are throwing up food that you ate previously. I thought it was just nasty junk coming out. It wasn't until age 8-9 and I got a stomach bug that I realized that what I was throwing up was that afternoon's lunch. It was even more revolting when I figured that out.
I heard my dad say that he thought the computer had a virus, and that made me worry that everyday objects could get "sick" and therefore spread germs if you tried to use them.
At school, my swim teacher told me to run to the changing rooms, dry myself and get changed as quickly as possible or else "a cold might catch me."
I think it was a cross between the myth that being cold or wet makes you catch a cold, plus her desire to make me not dawdle. I was always skeptical but I never outright disbelieved it until later.
She'd describe said "cold" as being a huge, slimy green monster and when it caught you, you'd sneeze once, then fall sick with a cold.
At one point, I sneezed and she jokingly said, "That cold has caught you!". It was actually hayfever, but I freaked out.
She'd sometimes state that she could see the "cold" and I was wondering why I couldn't.
When I told her that I'd never been assaulted by a green monster, she said that the cold must be a very slow runner or I was a very fast runner.
At one point, I was scared because I thought I had slime on me and that "the cold" had caught me, but it turned out to only be a snail.
I thought that you could only catch a cold in the winter. I knew that germs made you catch colds and that being cold alone doesn't make you catch a cold, but because it was called a "cold", I thought you could only catch one in winter. Then, Dad caught a cold in summer and explained that you could actually catch colds in the summer. P.S. he's fine now.
I thought a stomach ache was a stomach egg
I used to believe that when you throw up, you would throw up your internal organs as well as your food. I would always be scared when I had to throw up and I swallowed my vomit a lot of times because of this.
Until my mom told me the story of when she had the chicken pox on Christmas day when she was about six, I used to believe that it was physically impossible to get sick on a holiday, or on your birthday, because those days had magical powers.
I use to believe that if my hair fell out I had cancer, and was most likely going to die soon.
I use to believe that you would get ill because you were naughty
Since my brother always claimed he had the School Flu to get out of school, I assumed the School Flu was a real disease.
When I was little and I first heard of chickenpox, I asked if there was horsepox or sheeppox. When I was told "no," I assumed that cowpox didn't exist.
when i was a kid i used to think i got rashes and was itchy because bees flew in my ear and were flying around under my skin.
Since drinking after someone who was sick meant you might get sick, I used to believe that if you were sick you could drink after someone who was well to get rid of your sickness. This belief landed me a serious case of strep throat. I didn't believe it after that.
When I was a kid, I used to believe that everyone had two bugs in their stomachs... One to digest food, the other to pass liquid. Whenever someone had a stomach bug, that meant one of their bugs were sick.
I used to believe that when my hair fell out in the shower, that I had cancer. Later I learned that the amount of hair I lost daily was normal, not to mention that "cancer hair loss" is caused by Chemo, not cancer.
I thought that borderline personality disorder meant the person almost had a personality disorder, but not quite.
When I was a kindergarten student, I used to believe I could fly in the sky.
One day I tried to fly from the jungle gym and I broke my legs and hand.
When I was younger, I used to believe that "head ache" or "stomach ache" was "head egg/stomach egg", and I thought it hurt because an egg was growing inside of your head or stomach.
You know how some medicines and the like have the label saying "keep out of reach of children"? Well I thought it meant if a kid was in possession of it they would go to jail. I remember one time when I had Chicken Pox I had some lotion i could put on and my mom let me hold onto it but because it has the "keep out of reach of children" on it I was scared the police might somehow find out I had it and throw me in jail!