This is the "cumulative anger" effect. The multidimensional test evaluates not just the intensity of a flare-up, but also the frequency of irritation. If you brush off small annoyances all day, you have less mental bandwidth to stay calm—and any little thing can become the "last straw" that sets off a big reaction.
Studies show that levels of experienced anger are roughly equal between the sexes. The difference usually lies in the methods of expression: social norms often allow men open aggression (anger-out),while women are encouraged to suppress anger (anger-in),leading to different behavioral strategies.