There is no success without sacrifice. If you succeed without sacrifice it is because someone has suffered before you. If you sacrifice without success it is because someone will succeed after.
I've come to embrace the notion that I haven't done enough in my life. I've come to confirm that one's title, even a title like president of the United States, says very little about how well one's life has been led. No matter how much you've done or how successful you've been, there's always more to do, always more to learn, and always more to achieve.