Introduction: The instructions are geared toward the idea of fitness within the martial arts. I offer Chinese calisthenics, more so on the fitness than fighting while learning the art at the same time.
If you're not in basic shape, being a black belt won't help.
Being able to help people learn is the happiness any instructor enjoys -- if I do say so myself, especially when clients told to me that it helped them save their life or protect someone else's, even prevent an injury.