Words stay out in the world forever. While apologies and making up help people heal to some extent, the pain persists and accumulates. The tally of hurts add up. Each repetition touches the nerve irritated by the past hurts and traumas. There's a geometric progression. Finally, all put-downs, hot-headed yelling, and other minor abuses leave the victim feeling manipulated, used, and beaten.
The divorced woman relives her broken heart when her new husband lashes out in frustration over his own insecurities. The husband who survived a childhood of poverty and abuse hurts extra when he's unemployed and beholden to others for his privileged lifestyle. The mother releases her tensions on her daughter. The son mad at his father says what he knows will hit below the belt to his mother, whom he knows will love him unconditionally.
People relax, forgive, feel better over time, but what's been said lingers. Those statements reverberate and the damage persists. Sometimes, it's a fault line in a marriage, whether there's eventual divorce or not. Sometimes, the child pays a price psychologically forever and it plays out in future relationships and emotional disturbance.
It takes courage to write off those words which are unwarranted and credit them back to the disturbance of the verbally abusive other. It takes intelligent objectivity to determine if any complaints, even if their deliverery disgusts, acturally warrants some consideration or dictates the needfor change. Most of all, it takes emotinal maturity to self-comfort and heal from the inside, not counting on the other to do the work nor giving him/her the power to control every emotion.