There is no stability in the world. We live in a world of processes. The man himself is a process. Everything changes. something fast, something slow. In our nature, this is the way, if there is no development, then there is death. There is nothing superfluous or unnecessary in nature. Everything that nature does not use, it removes as superfluous. In living nature, organisms grow, develop. To do this, they overcome the resistance of the environment. After all, it already has everything you need, and the body squeezes itself. for example, a person constantly overcomes gravity, temperature changes, bacteria. We have such a need-to overcome difficulties. It strengthens us. However, the difficulties are too heavy, then there is stress. But you can overcome it, if you understand what caused it.