A thin red line.
I've never been the best at expressing myself in writing. (Excepting blogs where sarcasm is to be expected.) My email writing style tends to often be read wrong as either insulting or cold, when in fact, I'm just trying to be funny.
It's gotten worse now that I'm in the working world. I haven't quite finessed the proper letter writing style. It's that whole trying to balance formality with friendliness. I try to be professional, but when I read it back it sounds very cold. But if I'm too friendly, I sound un-professional. And as a young lawyer, I need all the help I can get in sounding like I know what I'm doing.