The derogatory or condescending e-mail

Electronic communication is efficient, but it's detached. Sitting at a computer screen, the need for tact and a respectful tone disappears.

• Being on the receiving end of such impoliteness can create lingering stress and negative emotions. The recipient may find it harder to stay engaged at work. The stress associated with e-mail rudeness can spill over into family life and, like a chain reaction, can send stress signals to other people.
• A subtler form of aggression is failing to reply to a request, in effect giving others the "silent treatment." Not responding to an email leaves people hanging and struggling with uncertainty.