What are your first principles (rules you've developed) in your life?
People who make me feel like crap or worse off then when I encountered them consistently are written off and out of my life
Doesn't matter if its family, nobody is entitled to your attention and suffering and it does nobody any real good for you to succumb to the inevitable dysfunction it creates in your life and relationships and also material conditions.
Treat others the way you'd like to be treated. When I call customer support, I don't get mad at the person because it's not their fault. If someone flubs up my order I don't say anything. I try to smile to everyone even though I don't want to. Even if I don't make their day better, I try to make it at least bearable.
If someone flubs your order, you can still say something about it. Just be friendly and understanding about it instead of an entitled asshole like some people.