Emotions were meant to be felt.
It is the act of feeling them that frees us from them.
Pushing them down lets them grow and fester into monstrous manifestations of inexplicable aberrant behavior.
It’s so much harder to grapple with them then, and they are often mutated and unrecognizable compared to the original emotions that created them in the first place.
Unprocessed emotions and events “clog the works” and either keep us from feeling other incoming emotions like happiness, or mutate our response to them into the abnormal realm (i.e. not equal and appropriate responses but rather “flying off the handle”, etc.).