Empathy
Not an easy trait but totally worth learning.
It is easier if learned as a child, but even as a grown-up, being empathetic would save you a lot of headaches, helping you to understand why the person you interact with acts as they do. You don’t even need to agree with them, just understand what might be going on in their lives. What the stressors are.
Being empathetic helps you too; once you know how to, you can be less critical of yourself. I can be more empathetic with myself.