You have to have a habitual vision of greatness ... you have to believe in fact that you will refuse to settle for mediocrity. You won't confuse your financial security with your personal integrity, you won't confuse your success with your greatness or your prosperity with your magnanimity ... believe in fact that living is connected to giving.
Greatness is telling the truth & being courageous in pursuit of justice. The worst thing you could tell young people is to be successful but become well-adjusted to an unjust status quo as opposed to being great & being maladjusted to an unjust status quo.
I'm a Christian. I believe that greatness has to do with the quality of love shown to the least of thy brethren and the quality of service to those who are catching hell. When you look at it in that sense, I'd say America has had great moments, but I wouldn't call it a great nation. I don't think there have been any great nations in the history of the world, because in every nation you find poor people being subjugated. So, I see the term "great nation" as a contradiction, as an oxymoron.