menachem, that’s a machlokes in the gemara; if daagah should be yasichena, or yashichena, i.e. destroy it
either way becoming emotional doesn’t equal ka’as – if someone cries bitterly and vents their suffering, thats not calm and collected, but it’s not anger either.
even if someone’s angry, it should be stressed again that the OP is right about not bottling it up…it just builds and builds. To fight anger, and other middos, you need to bring in something positive against it; whether that’s meditation on maamarei chazal about anger, or reminding yourself constantly that everything is from Hashem, and good, so there’s no source of the anger to begin with.
Anger is essentially the frustration that comes from not getting what you’re expecting, whether that’s material loss or lack of gain, or the way people treat you. but if you knew for certain that these things were for the best, you wouldn’t be angry – if someone steals your parking spot, but you found out later that there was glass all around it, and it punctured the other driver’s tires, you’d feel relieved, not angry. So if Hashem decided that this parking spot is bad for you, for some reason, it should be enough of a reason not to be angry.