I was skimming jkOnTheRun  and he linked to an article called The Tyranny of Email. The article isn't very exciting, but there were a couple points that caught my eye because they're crappy things that I keep doing but shouldn't be. For example:
"First, never, ever, criticize someone in email. For reasons which I have never fully grasped, any negative emotion is always amplified by communication through email. Sometimes you intend to be critical - someone has done something dumb, or said something silly, or emailed something ridiculous. Resist the urge to reply. Sometimes you don't mean to be critical - you're just making an observation, or engaging in technical debate, or adding facts to a discussion. But as soon as you sense that the recipient has taken your email as criticism, you must immediately switch media - a face-to-face meeting is best, but a 'phone call is also okay."
Also this one (less so):
"Second, don't get into prolonged technical debates in email."
Usually, the "technical debates" I get into over email are less "technical" and more hyperbole. All hyperbole is bad! 
 Every time I look at "jk", I think he's just kidding. It's confusing.