People do what they do because of motivations. If you were to grasp another person’s motivations, you would need to understand why they perform certain activities. It all begins with identifying what they need i.e., what are their goals, dreams or ambitions; as these are their motivating waking forces.
Beyond mere desire or aspiration, motives encompass other elements. But the question remains – why do they seek it? It could be that your protagonist seeks for justice because of some past traumatic events while the evil character might be in search of power as a form of validation. When you remove these outer coverings, you end up having people who have more than one side to them; they are the best type—dynamic and with depth.
These are no longer flat characters but full-blown human beings who have wants that resonate with fear and hope so much that audience’s heart will be touched by their emotions
Brandon McNulty explains about “Character Goals and Motivations”.