Doing tai ji, gong fu and qi gong has changed my life. One of the biggest things I have learned has been consitency and discipline, which means doing the practice every morning of my own volition, despite how I am feeling.
Ultimately I have learned that the martial arts highest aim has nothing to do with violence. It has everything to with ourselves and nothing to do with an opponent. By knowing ourselves and taming our impulses we gradual move into the spiritual meditative side of things. From there we learn to maintain a calm state which isn't disturbed by everything.
Exactly, even in disciplines like karate, you get to a point of realization that when you face someone in a contest fight, you are testing yourself in different in both physically and mentally. By practicing martial, you have the possibility to correct some vices and flaws. You can get a different perspective.