If I had thirty seconds to tell the world anything, I would say:
Try to be happy as often as possible. There will be times when adverse conditions stare you straight in the face, try to make the most of it and realise that if you work hard enough, you can pull yourself out of any mire.
Learn to appreciate the stranger things in life. The little, unique things are the best ones and if you learn to take notice of them, then the really large things will seem far more interesting.
Find one unique thing about yourself and exploit it to it's full potential. Maybe you're an excellent kazoo player, maybe you have a garage band, maybe you write commentaries for your school newspaper. If you find a way to do what you love, then NEVER turn down the opportunity because you will want to kick yourself in the face for missing the opportunity later.
Let it slide, once in a while. Fretting over every small detail will do no good because, frankly it makes you and everyone else around you extremely frustrated. This, of course should be handled strictly on a case by case basis. I feel obligated to say this considering the fact that you might be an air traffic controller, or CFO for a large corporation. THEN, you fret over the small stuff, but only to a prifessional capacity.
Live long, live happily, and remember that what everyone else says or thinks is total garbage when it comes to who you are.
That's what I would say.
What would you say.