The World of Kung-Fu 1.4: The Psychology of Kung Fu
Becoming a master of Kung Fu changes people in many ways, but two stand out in particular. Firstly, humans with very high levels of Health tend to feel good. They are more likely to be happy and less likely to be depressed than the average person. The joy of life that can accompany extreme health can be quite a serious problem for those martial artists seeking to lose their attachments and reach enlightenment.
Secondly, many martial artists meditate, and meditation inclines people to either become more compassionate or to become more detached and callous. In effect, meditation makes good guys kinder, but bad guys crueler. The Shaolin monks and Wudang priests in particular meditate a lot and have become very compassionate.