Not my current username as far as I recall... But, back when I was still An-chan, people would often write an uppercase C, which is something I couldn't stand xD Not that it bothered me too much or anything. I just noticed it every time, so it made me a bit harder to concentrate on what came after the typo'd username.
I'm not really too sensitive about it.
My real name never gets pronounced correctly by foreigners, save for Japanese people, since their language is generally pronounced similarly to Finnish. An English-speaking person has never, ever pronounced my name correctly, but again, I'm not too sensitive about stuff like that.
Oh, and don't even get me started on my last name xD