This "training" has actually been taking place for years and years. Think back to your early years, that time when you were finding your niche in life. You pushed and pushed yourself to achieve your lofty goals: doing well in school, getting that first job, finding a career, excelling in your career. Feeling the resulting stress became a natural feeling that went along with each wonderful accomplishment. The stress became a sign that you indeed were working hard, a personal indicator that you were driving hard at your goals. It didn't take long for your subconscious mind to began viewing stress as positive reinforcement. So the danger begins.
Some have conditioned themselves so much in the past, associating stress with achievement, they never find the internal peace/confidence that should come with maturity. They subconsciously believe that if stress isn’t present, it must mean they aren’t achieving/working to their fullest potential. To them, both are subconsciously necessary. Now, the rational mind knows this is not true. You do not need to feel stress to be successful, but years of conditioning have formed a different belief. And so, to feel “whole,” many seek out stress, as stress and achievement are now subconsciously inseparable, forever linked.
This does not mean we should avoid changing, growing, moving out of comfort zones, challenging ourselves, and doing our best - quite the contrary. A rich, full life depends on changing, growing, and challenging oneself always. It simply means that we need to look carefully at the stress we are feeling as we move through life, as we move through our challenges. We need to take greater comfort in our maturity, in our abilities, and in our skills honed throughout the years. We need to work on losing the incorrect belief that stress is a good indicator that we are excelling and doing a good job. It is a dangerous association that our subconscious mind created, a dangerous association that robs us of the true beauty of the present, the true beauty of our lives.