When I was in secondary school studying home economics ("food technology" to more 'modern day' students or just plain 'cookery' to older ones), we had to prepare a full breakfast. I got the mistaken belief that I somehow invented hot buttered toast.
Well, I had never seen it before and therefore it was a 'new invention' for a 12 year old... But I am *so* glad now that I didn't actually reveal it to anyone...
A childhood belief about general

others believed things like this
- I used to think that the sleep in my eyes at the breakfast table were toast crumbs.— crawford
- I believed that my mother invented toast.— Helen
- i used to think technology was "flying cars" and that we would have them by the year 2000.— josieg
- I used to belief sloths lived in trees outside my childhood home. My older sister told me so.Anon
- I thought that Devil's food cake was invented by Satanists!— Dietrich Corby
- I use to believe that everyone in Florida didn't go to school because it was warm all year around.— Julia