You are doing it to have a life. One of PG's essays talks about compressing the amount of work you do into a few years and then you have, if successful, financial independence and no need to work for the rest of your life. Though like PG after attaining financial independence you will likely start more companies and keep working. I would doubt that you would work as hard as you did during the startup though and I imagine your goals in each company would be more altruistic than if you had to live paycheck to paycheck.<p>That being said working like crazy at a startup might not be the way that you want to spend your time. There are many paths to Rome.