I recently stumbled upon a commencement speech by Marc S. Lewis given in 2000. I found it to be very inspiring and thought provoking and would encourage you to read the entire speech which can be found here: http://homepage.psy.utexas.edu/homepage/admin/Grad/lewis.html. Below are three excerpts from the speech that I especially loved.
"There are times when you are going to do well, and times when you're going to fail. But neither the doing well, nor the failure is the measure of success. The measure of success is what you think about what you've done. Let me put that another way: The way to be happy is to like yourself and the way to like yourself is to do only things that make you proud."
"The way to be happy is to like yourself. That’s the real reason not to lie or cheat or turn away in fear. There’s that old joke, not very funny, that goes "no matter where you go, there you are." That’s true. The person who you’re with most in life is yourself and if you don’t like yourself you’re always with somebody you don’t like."
"...whatever strong belief you now hold about what it means to be successful, I hope you will stay open to the possibility that you’ve got it all wrong and graciously accept your new awareness when it comes, with gratitude and humility."