For example, if Tom doesn't get his way, he shouts. He insults us. He makes a scene. To prevent the scene, we let him have his way. Don't cross Tom, he explodes.
Difficult behaviors are finely polished.
They are skilled preformances. You can't change them. But, you can change how you respond to their difficult behavior. Secondly, then, don't try to change them. Rather, change your response to their difficult behavior.