Fly off the handle Informal

To suddenly and unpredictably lose one’s temper, often over something relatively minor.

The suddenness is the key part of the image — there’s typically little warning before the outburst, making it feel disproportionate or startling to whoever’s on the receiving end.

The image is literal and physical: a poorly fitted axe head could work loose during heavy chopping and fly off its wooden handle without warning, becoming dangerous exactly when least expected — an 1828 newspaper account even describes a real accident of this kind, in which “the axe of one of them flew off the handle and struck his brother.” The figurative sense for a sudden loss of temper appeared in American English print by at least 1816, in Maine’s “Portland Gazette and Maine Advertiser,” describing politicians ready to “fly off the handle” over a dispute, meaning the metaphorical meaning was already established in political writing before the record of an actual handle-related accident that might seem to explain it — a reminder that a vivid literal-sounding origin story doesn’t always predate the figurative use it supposedly inspired.

He flew off the handle when he saw the parking ticket.

Try not to fly off the handle over small mistakes.

She flew off the handle at the slightest criticism.

A: “Why is he so upset?” B: “Someone made a joke and he just flew off the handle.”