Lama Ole’s answer:
Most people have little control over what they experience and how they experience it. They depend on outer conditions and their mood—meaning that they are nice when they feel good and difficult when they feel bad. Recognizing this, you can try to bring them into the best possible situations, so that they do as well as possible. This helps them have the chance to be nice. This way, so to speak, the stone rolls more and more often into another, better direction. They can create the habit of playing in the comedies of life rather than the tragedies.
You should not let yourself be disturbed by difficult people. Just think that they behave as well as they can and that they don’t know any better. Don’t take things so seriously and personally.
However, one shouldn’t become too overconfident in this regard either. If your fellow human beings call your attention to the same flaw in yourself again and again, and yet you’re convinced that all the others are wrong, then you’d better examine yourself carefully.