I used to spell ridiculous "rediculous" for a long time.
I always assumed that it was using the "re" prefix to "diculous". I realize "diculous" isn't a word, but it just seemed so natural.
Then I finally f*cking realized it was adding an "ous" ending to "ridicule," which I always spelled right to begin with.
Even now though, "rediculous" is still how my brain thinks to spell it, so every time I type that word out I have to make a conscious effort to recognize I'm typing it and go back and fix it.
It's nice having a built-in spellchecker in my brain.
It makes up for not having many childhood memories.