An excerpt from Steve Jobs 2005 commencement speech at Stanford University:

“For the past 33 years, I have looked in the mirror every morning and asked myself, “If today were the last day of my life, would I want to do what I am about to do today?” And whenever the answer has been “no” for too many days in a row, I know I need to change something. Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart.

- See more at: http://blog.loubopp.com/page/23/#sthash.iekI7J4v.dpuf