I think you might be conflating owner and CEO. Owners often don't have to work every day after the business is running smoothly and they have hired good people to manage it. CEOs have to work every day just like all other employees and they have different types of stress than the typical employee. Sure the CEO probably doesn't have to worry about money or about getting fired (mostly), they still have plenty of stress because their job is to always deal with the worst problem. The problem no one else can handle or wants to handle. Plus they have to worry about the business as a whole and they understand that if they screw up, 10s or 100s or 1000s of people are hurt.