In defining my thoughts on leadership, I believe it can be explained as the difference between saying "do it my way," and "join me over here."
When I think of great leaders, I see a lone figure already in the place they want to create. Between them is the void and everyone else's present reality. Great leaders encourage others to let go of this reality to work on possibilities.
Neither characteristics of a boss or manager make for a leader. It is important to be honest enough to admit which one you are.