Most people underwrite their stories. By that I mean that they don’t write enough. Instead of letting us know and understand different characters, all we see are two-dimensional portrayals of these people. In bad movies, only the good guy seems to have a goal of any kind. The other characters exist solely to help advance the plot by making the hero’s life easier.
Watch “The Day After Tomorrow,” which is one of those disaster movies about climate change. From a story point of view with its special effects of world landmarks getting demolished, the movie works. The main story is about the hero trying to find his son and all the other characters around help him. Yet we never get to know why these other characters want to help the hero or if the world is ending, don’t they have loved ones of their own that they would want to help?
By only showing us other characters willing to help the hero but not revealing their own goals and motivations, these other characters come across as nothing more than plot conveniences to move the story along. Either the writer didn’t know why these characters existed, or the writer never bothered to tell us. Either way, such underwriting leaves us with a thin story.
Now look at the scripts of Quentin Tarantino, who tends to overwrite his scripts and winds up cutting much of his script away in the final film. In “Django Unchained,” there’s a long story about how Django’s wife got separated from him and how her previous owner lost her in a poker game to the cruel plantation owner. While interesting, all of this background story has no relevance on the main story, which is Django trying to find and rescue his wife. However, this information leaks out a bit throughout the story, which makes Django’s wife feel more real because of such tidbits of information we hear about, although we never get to see it.
In “Inglorious Basterds,” the opening scene shows a French girl running away from the Nazi Jew Hunter. Then in the script, there’s a long sequence where this French girl becomes the owner of the theater where she’ll eventually kill a bunch of high-ranking Nazis. Although this backstory got cut, the hints that it provides makes this French girl seem more real and fleshed out as a character from what little we do learn about her past. By overwriting, Quentin Tarantino makes his stories deeper and more interesting, even though we never get to see all the parts he cut out. Because there’s more than what we see, his characters have a reason for doing what they’re doing; they don’t exist just for the sake of helping the hero.
When in doubt, overwrite. You can always cut but if you don’t know your characters, you’ll only write a thin, two-dimensional melodrama with sock puppet characters who have little personality of their own. By overwriting, you’ll really understand the motivation of your characters, and that understanding will reflect in your final draft, even if nobody else knows the same background of your characters that you do.