Kung fu, while being a great way to get get into shape, is so much more than a physical activity. Of course there is all the character development that comes from learning discipline and respect, and there is the obvious self-esteem benefits: followers become leaders and angry people become calm and compassionate. The less obvious benefits from practicing the art, at least for those who never achieve the higher ranks, comes in the form of cultivating your chi, your internal energy.
Energy. Everyone has it but not everyone can use it. It takes years to develop your awareness of your chi and decades longer before you can control and use it. Using chi comes from mindfully practicing the six harmonies or more specifically, practice the three internal harmonies: sprit with intent, intent with chi, chi with strength.
From my experience, the biggest thing in the way of a person mastering those three internal harmonies is their attitude. When I say attitude, I mean the intent behind their actions — what is the thought process behind what they are doing?
Physical output requires engagement. Engagement of the muscles, and the alignment of the skeleton. Internal output (energy) requires letting go and releasing. Yes, a very abstract concept but nevertheless an important concept.
“The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.” - Edsger W. Dijkstra (1930 - 2002)