" . . . if you want to change the world . . . "

You might be surprised at what he has to say...
Advice from Admiral William H. McRaven, Commander, United States Special Operations Command United States Navy

                                                Video from May 17, 2014 . . . Commencement at The University of Texas at Austin

(the speech is available online in its entirety in video form and transcript, I would search for it if I were you, definitely worth your time)