Entrepreneurs live with risk and uncertainty. They don't have a choice. The future is up to them. They are responsible for their successes and failures, and success is never permanent. Therefore, Entrepreneurs have to learn to handle the risk and uncertainty of having to be responsible for their company and employees.
I have been fortunate. I have spent the majority of my life as an entrepreneur. In fact, I have never had a "real job". I started my first real company when I was in elementary school, and sold it when I was 20. I have spent most of my life focused on building successful and sustainable companies. My early start allowed me to adjust gradually to the risks and uncertainty of being an entrepreneur.
When I started I had nothing to lose. I started a business because the people I knew needed a service and I had time. Gradually, the risks and uncertainty increased. In order to increase profits I started to take on more and riskier projects. They required hiring more employees, purchasing more equipment, investing more money, and taking more risks. Over the years, I have been forced to learn to handle the risk and uncertainty of being an entrepreneur, both in the good and bad times. I have made and lost money, employees, and capital.
In good times, I learned to stay paranoid. In High School, after getting overly confident I learned the importance of Andy Grove's quote, "Success breeds complacency, complacency failure, only the paranoid survive."