Leadership, like anything must be practiced and honed. Very few people can get up in front of a crowded auditorium and speak without being prepared. Practice, rehearsing, and study are usually required to be successful in this regard.
Relationships as well need maintenance and work. Very few marriages can survive, let alone be successful if the people involved are not constantly trying to maintain it and make improvements. I can speak from personal experience that my wife and I are constantly doing things to make sure that our relationship stays healthy and happy. Leadership requires this same kind of constant vigilance. It is not always enough to sit behind the fancy desk and go to the important meetings, and make big decisions, leaders need to be thinking constantly about how to be the best they can be.
Often times you will see someone new to a leadership position trying to get better as a leader. They might ask for feedback, or employ new tactics to see what works best, and many times these efforts are effective. More often than not, however, these new leaders abandon these practices once they think they have a handle on their position. Of course, this is a mistake, and typically this failure to reflect and be vigilant creates problems. I have seen it first hand. You see it in marriages too, where a husband and wife work hard to get things on track, and once things start going well, they let up. Next thing you know, there is trouble and the wife runs off with her Pilates instructor. Bosses and supervisors need to view their leadership roles in the same way, or their employees will be off with the Pilates instructor or the hot new neighbor so fast it will make their heads spin. The work of reflection can never be over, or a leader will never reach his/her full potential.