Any time you watch a mediocre or bad movie, look for a theme. You probably won’t find one and that’s the root cause of bad stories right there.
Without a theme, stories risk drifting with no sense of direction or focus. Typically the screenwriter will simply write a bunch of disjointed scenes that may look interesting by themselves, but fail to link together, resulting in a choppy and uneven story.
Now watch a good movie and you’ll notice that not only does a theme exist, but it literally changes the hero emotionally. In the beginning, the hero is a flawed character. By the end, the hero has changed emotionally, usually for the better.
For an example of a bad movie, watch “The Spy Who Dumped Me,” which focuses on lots of action but by the end of the movie, does the hero really change?
Now watch a more strongly, emotionally grounded movie like “Booksmart,” which is about two high school girls who studied so hard that they never had much fun. Now right before graduation, they decide to have fun.
In the beginning of “Booksmart,” the hero wants to find love. By the end of the story, she finally finds love and she’s a changed girl.
A strong theme defines your hero’s emotional change. In the beginning, your hero is the opposite of your theme. By the end, your hero embraces your theme.
James Cameron tends to write theme-heavy stories so study his movies. In “Terminator 2,” the theme is that killing is wrong so at the beginning, the hero (the good Terminator) is a killing machine but by the end, he learns to value human life.
The lack of a theme is the reason why “Terminator 3” is so unsatisfying. Despite all the action and fighting, there’s no emotional change so the story is far less memorable.
A theme defines the emotional change in your hero. Without this emotional change, even the most action-packed story will seem pointless. With emotional change, even the simplest story takes on far greater significance and meaning.
Start with a theme. Then your theme will help define your characters and the obstacles they need to face. Without a theme, you risk writing collections of interesting scenes that don’t work together, and then you wind up with a forgettable story, and who wants to write a story no one will care about?