I think I can come across as fairly abrasive, in particular when I type things out online and often give people the wrong impression or come across as disliking people when I don't. I'm pretty blunt in real life too but there I have my natural charm and winning smile to smooth things over(cough).
PS: I hear this is one of the most popular questions now asked in job interviews as well, so it might pay to come up with something decent if you are job hunting.
Everything is a short-coming. Even though I excel at some things more than others, I can always do better and I won't stop trying.
Tip: Don't ever tell a recruiter or hiring manager that some people perceive you as rude, online or url.