Good versus Evil is the oldest conflict in the history of mankind. Truth be told, the particulars of what makes each one what they are is extremely relative and also open to interpretation. And it's those interpretations that make them so fascinating. Fairy tales, religious stories, cautionary tales; every kind of story you can think of ultimately hinges back on that one basic conflict in one fashion or another.
Now, when most people apply that to life as many tend to, it creates a very black-and-white perspective. The media obviously has been capitalizing on this ideology for as long as there are been means of communication. Cowboys and indians, cops and robbers, man vs. beast and so on and so forths; these stories have always dealt with a protagonist and an antagonist, a hero and a villain. However, one of the unfortunate tendencies during those times was to vilify beings or entities that weren't understood at the time or that propaganda ruled as "the enemy". The idea that things weren't as black-and-white as those in control of the media flow wanted you to believe wasn't a popular concept in the earliest days of fiction. But it's my belief, that those are truly the best stories.
Now, anybody that knows me knows my love of superhero stories. But one thing that is evident, in the earliest renditions of superhero stories, they were basically black-and-white stories of a grandiose, benevolent hero fighting stopping the machinations of some criminal or super-villain. But ultimately, they had the tendency to fall under same black-and-white purview as all other conflict based fiction. Finding the point of the deviation from this norm would make from one hell of an essay, but I don't think I'm the guy to write it. LOL
I guess what I'm ultimately driving at is the basic idea of the gray area... the balance. I believe that the universe abhors a vacuum and that, if it exists, it likely serves a purpose of some kind. Without evil, there's no good and vice versa. Thus, when it comes to telling stories of the greatest substance, there's a degree of understanding that's necessary to tell the most well-rounded story possible, regardless of the genre; push and pull, action and consequence, good and evil.
You'll often hear that people say that the villains are the more interesting characters, but they wouldn't be if there weren't "heroes" to contrast them. So, it's always best to remember that "good vs. evil" is only boring when you don't understand what goes into making each side what it is. So, the best advice I can give is the best advice I've ever received; "a protagonist and antagonist are not restricted to being good and evil respectively and a good story doesn't require them to be". Take heed and keep striving, y'all!