Go make a mistake. Go do something that you will likely fail at. Pick a fight with someone bigger than you. Get your face punched in. Twice. Challenge something that you think is black and white. Stretch your mind as to see the other side of the coin. Dare to upset the silence. Jump off a cliff first, not because everyone else is. Fail and then try again. And then again.
Be the best you that you possible can be without care or weight to outside naysayers and critics. Live your life. You being the best you is the best thing for the world. Do the things that make you come alive, that make your hair stand up on end and that scares you to the point of joy. You only get one go around in this life, don't leave anything on the table.
"Fall seven times. Stand up eight." - Japanese Proverb
"Keep away from people that try and belittle your ambitions. Small people always do that, but the really great make you feel that you too can become great." - Mark Twain
"The US Constitution doesn't guarantee happiness, only the pursuit of it. You have to catch up with it yourself." - Benjamin Franklin
"The last of human freedoms, to choose one's attitude in any given set of circumstances, to choose one's own way." - Victor Frankl