I write because it is cathartic. Those stories need to come out and those characters need to live.
I have more fun exploring them than I think I should.
To me, the payout is putting those words on the screen, whether or not the rest of the world will ever see them.
I journey along with my characters (I cannot get into detailed outlines for the life of me) so the exploration, the journey is just as much fun writing as it (hopefully) will be for anyone who reads it some day.
Great question!
