In my experience, there are two reasons to practice a martial art. One is to defend oneself in situations with violent potential. The other is accumulation of mastery of self through the practical study of Qi. I am not a master, far from it. My level of accomplishment is relevant to the credence you can give my opinions and so I give my perception of my skill. I consider my position on the scale of skill to be just over the line between beginner and intermediate student.
Both purposes are served by the practice of a fighting art. Even if the person's only objective is acquisition of combat skills, mastery of self is necessary and learned whether it is taught directly or only implicitly. Just as important, the student learns about the nature of oppositional relationships from an instance which lays bare the most important principles of the nature of oppositional relationships. This knowledge can enable you to resolve conflict without violence; physical or otherwise. And perhaps more importantly its transferrable to oppositional relationships in almost any circumstances.
Qi and Yin & Yang are the most common tools used in discovering and understanding the lessons of fighting arts. Practicing a fighting art requires not only a healthful level of Qi but the ability to gather and direct it. Yin & Yang - The Law of the Unity of Opposites - has five aspects that are points of departure in the analysis of conflict. To apply this yourself you can take the list of Yin & Yang characteristics and identify which are present in a fight. Below, an example: A disagreement between co-workers that grows heated.
Everything has two opposite aspects. Yin & Yang struggle with and control each other.This defines conflict.
One worker becomes aggressive. His back straightens, his breathing deepens, he leans forward and his voice grows louder and faster.
Yin & Yang define each other and therefore one cannot exist without the other.
If only one person is willing to contend, conflict does not arise.
The other worker only listens and maintains his body posture, giving no hint of readiness to fight. He says thing that are only acknowledgments of the first worker's words, neither disagreeing nor agreeing.
3) MUTUAL CONSUMPTION & SUPPORT
Yin & Yang each give of themselves to nourish the other.
Each provokes the other who responds with aggression. This sustains the conflict.
The second worker also straightens his back and leans forward as he speaks louder, signaling a readiness to fight.
Yin can become Yang and Yang can become Yin. In fact, this is inevitable if the growth of one or the other is uncontrolled.
One aggresses (Yang) and the other parries (Yin). The aggressor intensifies the attack until the other counterstrikes. The counter strikes are the beginning of a counter-attack. The fighters have exchanged roles.
In response to the Yang actions of the first worker, the second worker adds to his noncommital verbal parrying arguments that counter the first worker's assertions.
5) INFINITE SUBDIVISIBLITY
There is always a bit of one in the other. Anything can be subdivided again and again.
In many styles there are moves which are both defensive and offensive. A parry not only neutralizes an attack but presents an offensive threat.
The second worker uses a combination of calm physicality and verbal sallies that threaten consequences if the aggrressing first worker does not cease his attack.