Leadership is not as easy as it seems. In order to be a successful leader, you need to have love for the thing that you are leading. That is why lost love would have to be number one on my list on why leaders fail. To be a great leader, loving the thing that you do would push you through the hard times that that job may give you. For example, Bobby Bowden has been a college football coach for many years. He does it because he loves the game. He loves making an impact on another kids life. If he did not love the job, he would not have stuck with that job for so long.
Second on my list is a shift in focus. You must be focused on what you want to accomplish so no peripheral sights my blindside you. Third on my list would have to be the slipping of the ethics. Ethics is the background to be a successful leader. Your work ethic and integrity can take you a long way. Communication skills are also essential when dealing with leadership. You must be able to communicate freely with your followers. Without communication, it would be hard for you to obtain information from any of your followers. The last two are just as importatnt: risk aversion and poor self management. Risk aversion is people simply thinking too much about the outcome of something and self management is how you manage to take care of yourself.