It's not the lies.
Nor is it that social-media thing whereby you exclude everybody who might disagree with you.
It's the self-belief.
The answer to
"Here is the incontrovertible evidence that proves you wrong."
"I know what I believe."
But that's understandable.
In our culture, the rebel always beats the empire.
We're disposed to take on causes.
The emperor doesn't have much of a dress sense, and the answer to the question "The 'empire' would do that, wouldn't they?" is not clear-cut.
Sooner or later, we all learn how to handle being mistaken. And occasionally just flat-out embarrassingly wrong.
We all experience that awful moment - you storm out, slam the door ... and realise that sooner or later, you're going to have to un-storm your way back in again.
Concede defeat, in other words. It's part of growing up.
The wisdom, at those moments, is to be found in the faces of the other people in the room, the parents let's say, who carry on as though nothing has happened, not looking at you, not reacting, letting the situation stabilise.
You gather up your toys and climb back into your pram. Life goes on.