Over the past couple of years, I've seen several major problems that were created or exacerbated by the extensive and loose use of email.
The distance that brings out trollish behavior on the Internet has a near but less extreme relative in email messages. You can find email exchanges that never would have become sarcastic or insensitive if the two parties were talking face to face or over the phone.
It is as if email has become synonymous with "abrupt message." People focus solely on the text and forget the tone. Sometimes, the text itself is questionable. If haste makes waste, rushed makes rude.
Unless we are willing to dedicate the time to craft the right tone, the use of email should be curtailed. Even if time is given, it should never be used to discuss sensitive topics. Email saves no time if it produces conflict, confusion, and hurt feelings.