going postal

Suggestion--don't say (or write) "going postal"

The writers using the expression "going postal" may not realize that it refers to a real series of crimes that happened  years ago. A "disgruntled postal worker" walked into a post office and shot several people. The crime seemed to inspire "copycats", and  "going postal" became an expression for going insane. This was later the subject of a movie--but the crimes were real, and the victims are dead. So it's not an amusing expression.