Did you
know?
go postal
This interesting phrase originated in the USA in 1990s, where there were several incidents of people going berserk and shooting numerous members of the public in post offices.
a close synonym is "to go ballistic", other related words are:
berserk, bitten, bugged,crazed, crazy, delirious, deranged, extreme, fanatical, flipped, frantic, freaked out, frenetic, frenzied, furious, hot, hydrophobic, infuriated, insane, intemperate, intolerant, irrational, mad, mad-dog, maniacal, narrow-minded, nutty, obsessed, overboard, raging, sizzling, smoking, steamed up, stoned, ultra, ultraist, violent, wild.