There are things that are fun and then there are things that are not. Being on the receiving end of a scathing email is most definitely one of the "nots."
Ever wonder why this occurs? I do. While my own personal opinion (read: rant and rave) may be of interest to some, it would not offer much in the way of constructive reasons. Instead, I would like to refer you to Will Schwalbe's post on Brazen Careerist, Send: Why Good People Send Savage Emails. Will offers some excellent points and one that I found insightful was the result of a study that concluded that the pain we receive seems more painful than the pain we produce.
Knowing this can provide you with a healthy perspective when a scathing email arrives in your mailbox. You know how it goes. . . your heart is racing, hands shaking, and you are literally ready to pounce. What do you do?! Responding to these messages in kind is a lose-lose situation and any pleasure you may feel as you hit the send bottom and think, "I'll show you" will be short lived. As Will points out, in responding, you may be as responsible for the escalation as the other party.
So what do you do? You disengage. You put your hands in the air, step away from the keyboard and head for the nearest box of chocolate or your vice of choice. When you come back to the keyboard, select the email, and hit DELETE.
Still thinking about responding to that email? Don't, it really is not worth it in the end. You are better than that.