[...The expression "to go postal" emerged in the mid-1980s, following a wave of violence by post office employees, as a way of saying "to lose one's sanity and attack others with weapons, especially to attack one's co-workers or boss." The wave of murder by post office employees that inspired the expression lasted for fifteen years, from about 1983 through 1998, with a mass murder in Oklahoma in 1986 standing out as particularly horrifying. Nobody has ever convincingly explained why this wave happened, though the hiring and management practices in the post office are generally blamed. They hire without regard to personality, and manage people like machines. Eventually, some go mad....]