Every now and then you will run into conflict. At work, at home, or inside your head. These moments are normally due to expectations that have not been met. They’re best treated as an opportunity to set or reset expectations around the topic.
Almost any destructive behaviour I can think of is the result of expectations not being met. A missed deadline is a missed expectation. An angry spouse is likely a missed expectation. A compulsive obsession is a missed expectation.
Be clear about what you expect of yourself and others. It matters perhaps more than anything else.