" your “4 minute mile”? What bill of goods have you sold yourself as to what’s impossible? What false assumptions are you making in terms of what you cannot have, do and be? Your thinking creates your reality. If you think something cannot occur in your life, then there’s no way you will take the action required to make that goal a reality. Your “impossibility thinking” becomes a self-fulfilling prophecy. Your perceived limitations become the chains that keep you from the greatness you were meant to be. And where’s the leadership in that? "

― Robin S. Sharma , The Mastery Manual