When I was little, my older brother told me that "ditch" was a swear-word. I used to call people 'stupid ditches' under my breath (stupid was also a really bad word)
I also believed that 'Fuddruckers' was a curse-word. (Fuddruckers is a restaurant, just in case you didn't know...)
A childhood belief about swearing

others believed things like this
- i used to think that the word "stupid" was a curse word, ranging in scale right beside the "f" word.Anon
- i used to think the word "suck" was a swear wordAnon
- I thought "sake" was a curse word— shh
- I used to believe that bizarre was a swear word.Anon
- I used to believe that “shut up” was a swear word.Anon
- i used to believe that if you said a swear word you would turn into the opposite sex the next day— jess