‘I don’t believe life has a purpose. Life is a lot of protoplasm with an urge to reproduce and continue in being… but each incarnation, you might say, has a potentiality, and the mission of life is to live that potentiality.’
Joseph Campbell is an incredible storyteller, spiritual guru, philosopher, academic (comparative religion & comparative mythology), writer, etc etc. Another old dead guy with a wicked sense of humour that I’m sure I would have fallen for in his day.
So “How do you do it?” you may ask. How do you live your life to it’s potential?
Campbell’s advice is: “Follow the bliss.”
‘There’s something inside you that knows when you’re in the center, that knows when you’re on the beam or off the beam. And if you get off the beam to earn money, you’ve lost your life. And if you stay in the cneter and don’t get any money, you still have your bliss.’ 
P284-5 Campbell, Joseph, The Power of Myth – Joseph Campbell with Bill Moyers (New York: Doubleday, 1988).