In my experience, good leadership is extremely rare in the civilian world. The U.S. professional military has very good professional leadership training, but when these folks transition into business they tend to get caught up in the awesome spectacle of the politics of business. Which is unfortunate, because following the politics of business is like listening to the devil. It's really not necessary. Business is about economics, and if they don't follow the economics then hanging on in a political existence is a choice. And then again, separating the social from the political in business is another rare skill.
From my own knowledge of professional leadership training it's very easy to say that the first most common mistake among the uninitiated concerns ego. Ego has no place in leadership, for a number of reasons left as an exercise for the reader. A classic cartoon in the military world of professional leadership is the characterization of a leader "as he sees himself", "as his superiors see him" and "as his followers see him". A great leader might have one of those on his or her office wall, or on the mind's wall. For perception and its estimation on behalf of others is a part of this human life, recognizing and shaping ones reaching is always important.
So, yes, life is messy. Philosophical distinction is the most important skill of all.