"Consider the attributes of a good martial artist. First, he or she must be healthy. Without good health, you cannot do much. Second, he needs to be physically fit, something everyone wants to enjoy. And last, a good martial artist has learned how to remain calm. He/she has learned how to stay calm, not just in everyday situations but in uncomfortable, dangerous, and even violent circumstances. In the world we all live in, gaining this last virtue is something that can be useful every day. Even if a student never needs to use taijiquan for self-defense, a martial practice is useful every day, for the everyday."
Quoted from my “Taiji Notebook for Martial Artists.”