If there is one thing I can't stand, it's when I start showing my true colors online and some idiot will start attacking me. Sometimes I don't do anything but voice my opinion, and I'll be accused of "fighting", "arguing", or even "attacking" someone. And this is when I know in my heart that I had no such intention, and only I know that for sure. A lot of the time it's their problem, not mine.
Online communication can really suck. Lucky for me I'm better than most because I'm a writer and I know a thing or two about expressing emotion and subtext using words alone... but obviously that doesn't help when the person reading the words is really thick-headed.