Uh, I'll go first. I can't say which stage of my life it was, but for about two years I believed I had an extra surname (side note: in my country it's normal to have more than one surname), so on my school documents I used to write: Nathaniel blah blah blah blah, Olixás De Oliveira. I felt desolate when I found out it was something I'd made up myself or had simply got confused about.