Plan for the future, live modestly, and invest diligently. If there ever comes a time when the work is no longer enjoyable or you are unable to get a job - go do something else!
Edit: I realized this is insensitive to people who are facing ageism and might not be in a position where they can retire or change careers. Not everyone will be able to retire early - everyone has different circumstances and luck plays a big role in life. But for anyone who happens to be in your early 20s and pulling in a 6 figure salary: if early retirement is something that interests you - now is the time to start saving.