The thing that holds them back, or raises them up. Because I do believe that how you fight your challenge determines how you're gonna make it. Presented with a problem, your challenge, and you roll over? This isn't...optimal.
But if you are presented with that problem, and you meet it, head on...unwilling to sit and whinge and say "I'm not good enough"...forgive the expression, but take that challenge by the b*lls and make *it* answer to *you*...well then, I think your chances are good at making this whole thing work.
Because there is nobody, anywhere, with a free ride. The piper always has to be paid.
My particular challenge is the deep fear that my writing is not good enough. I try to combat this challenge by writing varied, different things, looking for words in everything I see, and never.giving.up. No matter how much I want to at points.
You? What's yours?