Have the hard conversation when you’re calm enough to hear their side too.

A conversation you enter only to deliver your case is not a conversation, it is a speech with interruptions. Calm is not about being polite, it is about having room in your head to take in new information, including the kind that complicates your version. Without that room you will win and change nothing.

Before the next difficult talk, check whether you could summarize their side without sneering. If you cannot, you are not ready yet and the talk will go badly. Wait until you are curious about what they will say, even a little, and then go.