necessity of the villain

As I read Othello, I began to become very frustrated with the character Iago.  I couldn't understand why any of the characters couldn't see through his manipulative ways.  He somehow has the power to gain Othello's trust , which is a talent in itself.  Although it was my natural tendency to dislike Iago, I came to realization that this story would not have nearly as much substance with out his character.  Although Iago does not use his power for good, he still finds ways to control the other characters like puppets.  Do you think the story would be as interesting with out his character? Could stories (even movies) be interesting if they didn't involve a villain? So basically, although I dislike Iago's character, i have realized that Iago has to exist for the story to work. What are your thoughts? Do you agree?