When I was young, my mother would always say things were "as slow as a wet week". I realise now that this is a figure of speech referring to the way that things can seem really slow or boring during rainy weather.
I used to believe that there were these soggy, spongy creatures called "wet weaks", and I figured they must slop around everywhere incredibly slowly.
A childhood belief about speaking

others believed things like this
- i used to think mashed potatos were made from apples becouse they were the same color(i was a very slow child)— apples and ornges
- When I was very young, I thought that God was married to Mother Nature, and that together they made weather.Anon
- I used to think that the things you get in your teeth were called feelings.Anon
- I thought weather forecasters were psychic and that's how they knew what the weather would be.Anon
- when i was young i thought that a giant made the world slowly spin!— ~kassie~
- When I was young I want to grow up yo be a trash man, becuse they only work one day a week.— Steve H