Luck...................................

 Years ago I asked economist Robert Shiller, who won the Nobel Prize in economics, "What do you want to know about investing that we can't know?"

     "The exact role of luck in successful outcomes." he answered.

      I love that response, because no one actually things luck doesn't play a role in financial success.  But since it's hard to quantify luck and rude to suggest people's success is owed to it, the default stance is often to implicitly ignore luck as a factor of success.

-Morgan Housel, The Psychology of Money:  Timeless Lessons On Wealth, Greed, And Happiness