@#$Incomplete@#$ Endurance and development of mentality and emotionality

As how mass and strength of muscles and bones developed, as how body's flexibility developed, developing a mentality and emotionality needs some pressure and stress. Most of time, that pressure and stress are painful but mentality and emotionality actually strengthen by it. As far as I know of by my personal experience, being given pressure and stress is one of ways to develop. When I do weight training, my muscle not only gain more mess and strength, also gain an endurance. It's like get used to that pain so I don't feel pain as much as I used to feel before from the same degree of pressure and stress.