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.
What is success? I think it is a mixture of having a flair for the thing that you are doing; knowing that it is not enough, that you have got to have hard work and a certain sense of purpose.