My mum used to tell me that when the clouds were sitting low to the ground on frosty mornings it was because the fairies had been out late the night before and had not woken up to lift up the clouds yet. I believed this for quite a while.
A childhood belief about fairies

others believed things like this
- I used to believe that snow on the ground was clouds that were too tired to fly.— alex
- I used to believe that when it would be raining the white clouds lost to the dark clouds.— janet
- When I was a kid, I used to believe a nuclear plant was a clouds plant and could make magic clouds.— Tommy
- I believed you could sit on clouds. Anon
- When I was little, I believed that clouds came from paper mills.— Ryne
- I believed clouds were vanilla ice cream.— Ichi