All human development has been instigated by the need to address uncomfortable conditions and situations in life.
Problem solving is the impetus behind most of our creativity.
In like manner, stressing the physical body improves it as well. Our bodies become capable of handling more stress.
So we stress ourselves to be able to avoid stress; once we arrive at the place where conditions are comfortable and no longer need our attention; the inactivity and sedentary living makes us sick and weak.
It seems that challenges on all fronts is the catalyst for productive, healthy living.
Embrace discomfort as the muse of life!