I got some really evil customers on the phone when I worked in a call center 2 years ago as a supervisor...the worst one I got was a guy from Seattle that wished I would have been in the World Trade Center towers on September 11...only 2 weeks after the attack.
I think I still have my response to that around here somewhere...ah
here it is.
The cliche "Kill 'em with kindness" sounds so fucking corny...but you know what? It works the majority of the time.