I believe you’re right, it’s not great to assume this beforehand. Many things are negotiable, but there are a whole lot of things that aren’t.

When you’re faced with convincing someone of $TruthA or $FactA and one of those two collides with a persons worldview, makes them uncomfortable, or causes them pain. Sometimes that truth or fact will be thrown out because of its ramifications.

For example, if we’re in Iowa, and you prove to me that plastic straws don’t kill turtles.. but as a kid my first trip to the ocean resulted in seeing a dead turtle die to a straw. It’s going to be very difficult for me to believe otherwise.

My statement about a person not accepting something because they won’t want too… is less about them.. and more about the person trying to argue/explain/etc.

It’s important to identify when a topic won’t be accepted by an individual and to move on. It’s something I’ve struggled with in life. If you don’t identify it, you can risk overstaying your welcome. Which can lead to losing a trusted advisor status. It’s far better to keep the trusted advisor status and tackle the issue another time.

Well people love to try even though they always fail. It's a fun challenge to change someone's mind.

You don’t have to assume it, but you should be more than prepared for it to be the case

More than that, sometimes one side doesn’t want to accept something because everything they know about it says it’s wrong. Then they’re faced with evidence and reason prevails.

I usually have very strong opinions but try to hold on to them very loosely. It happened that I was convinced with evidence that I am right and refused to accept any alternative until new evidence slapped me in the face. At that point knowledge and discussion made me accept something I had previously thought preposterous, sometimes to the point of outright dismissing any conversation, this is how preposterous the proposition sounded at first sight.

What I want to say is that if you don’t know your audience, if you don’t know for sure your attempts are fruitless, it’s always worth a shot to use your knowledge in a discussion and let the other party digest that and see if it that moves the needle.