The villain of the story is always an interesting character that captures everybody’s attention, whether in fiction or in real life. Most viewers of a one-sided story would naturally side with the protagonist because it is from his or her side that the story is being told, and thus makes the audience sympathetic toward him or her. Of course, in literature and drama things are always exaggerated, and the fact that characters are either really naive and innocent or really cruel and evil makes the choice quite apparent. However, in good and complex literature, as in the real world where neither the best men are consistent in good nor the worst men in evil-- how are we to decide who is the good one and who is the bad one? It is up to each individual to decide based on their attachments, biases, and such.
I love studying literature because it is the study of the diversity of human nature and emotion, and villains always fascinate me. As a friend of mine said, "Without a villain, there is no story." How true! But who is the villain? From which perspective do we judge? As I always say-- "Your antagonist is a protagonist in the story in which you are the antagonist."