Michelle Obama: Always be happy; never be satisfied.

AP

"You should be so proud, and so happy, and so excited about your futures. But what you shouldn't be is satisfied... See, because we're the lucky ones, and we can never forget that we didn't get where we are today all on our own. We got here today because of so many people who toiled and sweat and bled and died for us -- people like our parents and grandparents and all those who came before them, people who never dreamed of getting a college education themselves but who worked, and saved, and sacrificed so that we could be here today. We owe them." ( Dillard University