First: Enlightenment, understanding the laws, conforming to nature, knowing cause and effect, knowing the future;
Second: Understanding people, understanding human nature, conforming to human nature, knowing words and actions, knowing good and evil;
Third: Understanding oneself, clarifying goals, knowing what to choose and what to give up, knowing when to advance and when to retreat.
The best state to maintain the distance between people is: being able to approach at any time and also being able to leave at any time. This is what the art of war calls "able to attack and able to defend." Don't completely immerse yourself in it, nor leave yourself without any way out. Maintain that sense of boundary, being neither too close nor too far, is the most subtle relationship, which will also make both parties comfortable. Don't keep the city gates tightly closed, nor leave them wide open, leave yourself some room, and also leave some room for the other party. You will always be the most welcome person.
A truly enlightened person is often a simple and unpretentious person. Without enough insight, you often cannot discover them.