Gunnysacking

Gunnysacking is when someone silently collects irritations and slights until "the last straw is placed on them" causing an overblown reaction. The term derives from the gunny sack, a cloth container used for carrying or storing things.

Gunnysacking has been described as "an alienating fight tactic in which a person saves up, or gunnysacks, grievances until the sack gets too heavy and bursts, and old hostilities pour out".