Discretion
This is why you should always re-read an email carefully before hitting send. For the truly paranoid, type it in a text editor and only cut-and-paste when you're happy with it, lest the email client auto-save a draft of a rash comment.
I use email, but there's stuff I've declined to send after typing and reviewing it, and times when I've gone to speak to someone or called them on the phone rather than put it in email because it's ever so easy to click "forward".
Biting the hand that feeds IT
