AlexK - Thanks for pointing out that "once you consider yourself the master/expert - there is nothing after that - you stop developing". This is very true, and this pitfall should be avoided at all costs if one is to attain true "Mastery" in the sense which I meant it, but which didn't explain properly, though I did hint in my words at a larger meaning.
When I said, "That is what mastery is all about - regular daily efforts and constant and never ending improvement," and "human potential is for all practical purposes - INFINITE," you might see that my idea of mastery isn't actually a set destination. It is a constant and never ending journey. For me mastery is about regular, disciplined efforts towards expressing our infinite potential.
I realize now, especially because of your comment, that my personal definition and understanding of mastery needed to be explained in greater detail - thanks for the nudge. My personal philosophy centers around this idea of mastery in the larger sense that I have outlined - it's a daily process for joyfully grappling with the Infinite. 
