Wow, Joe! Nice thoughts. I think that , if we say that is the biggest mistake we make, then certainly the second biggest is our deference to a "higher" being or "creator" to describe our greatness of self. I mean, why is it that we cannot be great simply because we are? Why is it that we decide it simply CANNOT be us but HAS to be someone or something else??

One must discover the truth that they themselves are makers of themselves by virture of the thoughts that they choose and encourage; that MIND is the master weaver, both of inner garment of character and the outer garment of circumstance and that, as they may have woven earlier in ignorance and pain, they may now weave in enlightenment and happiness. As a man thinketh in his heart, so is he.
I think that one need only look to themselves to see that our GREATNESS is us..what we are within.