Each of us has experiences and challenges that make us who we are and helps us formulate our personalities. This personality carries forward to determine how we interpret information and the decisions we make. In most cases we have no idea that we putting ideas through our mental filters and acting on that information in realizable patterns.
Most of us carry on those themes throughout our lives. Patterns can be positive or negative but when we meet people with poor patterns that might focus on self-indulgent or self-promoting behavior we might simply keep our distance. In the workplace there is a captive audience so it is important for people to work through their issues and ensure they are capable of leading a group of people.
Bosses who have gambling additions may steal, people with trust issues may do all the work themselves, hurt individuals could be chronically rude to others. If they are able to work through their issues they could be great managers but if they do not they will continue to display their patterns over and over. Great managers understand themselves before they start understanding others.