the audacity of ambition

I had an interesting chat the other morning with Rumon Carter, who can only be described as a modern renaissance man, due to his many talents.
A topic that we spent some time discussing was the "audacity of ambition," something that I think about quite a bit, due to many of the highly accomplished and highly ambitious people that I get to spend time with.
At the risk of sounding like Tim Ferris, or other life coaches, what I mean by that term, is how impressive it is to watch someone set a goal for themselves and then go about the process of figuring out how to achieve it and then taking the steps to make it happen.
I know that everyone is driven by goals, but for a lot of people and for most ideas, those goals never get past the dream stage, what interests me most, is the catalyst that pushes the idea out of that theoretical, "that would be cool to do" stage and into the "I'm going to try to make it happen" realm.

Why I consider it audacious, is because every personal goal is completely unchartered. Granted, one of the steps in the process along the way to the goal will invariably involve information gathering to some degree, where you seek you out a mentor, or research how others with similar objectives have gone about it, or are currently going about it, but the route that you end up will be entirely your own and frankly, that's an exciting, but equally terrifying thought.
Interestingly, the more clear the goal, the easier it usually is to chart your path along it. So the more time you can spend clarifying your goal to yourself, the better off you'll be.