Boundaries, respect and kindness are important for healthy interpersonal interactions. When a person consistently demonstrates a lack of those, I step back and my boundaries become harder, firmer. But sometimes, a person is just relentlessly negative and hurtful and over time as that continues, I lose the ability to give out more chances to that person and my willingness to empathize or try to understand that person’s actions or motivations just dissipates. The less I deal with that sort of thing, the happier and healthier I am.
It is sad - and thankfully fairly rare in my life.