The symposium was sponsored by the U.S. Postal Service, which has seen so many outbursts that in some circles excessive stress is known as “going postal.” Thirty-five people have been killed in 11 post office shootings since 1983.
to behave in a hysterical, angry or irrational manner
Hyphenation
to be·have in a hysterical, an·gry or ir·ra·tion·al man·ner