What makes a bad movie is when characters behave in ways that don’t make sense. A meek character suddenly becomes good with a gun, a villain suddenly attacks the hero for no reason, or the hero suddenly decides to save someone without any explanation. No matter how visually exciting the action might be, it will ultimately be meaningless if nobody understands it.
Think of the climactic scene of any good movie. When John McLane faces Hans the terrorist in “Die Hard,” we completely understand his motivation. First, he wants to save his wife. Second, he has taunted Hans over the radio for the longest time. Third, he actually came face to face with Hans without realizing it and was fooled by Hans. When John McLane finally kills Hans, we completely understand the motivation and we cheer when it happens because we’re emotionally invested in the outcome.
Now think of “Batman vs. Superman.” What’s the motivation for Batman to fight Superman? Supposedly it’s because Bruce Wayne is upset at all the destruction Superman caused while trying to save the city from a villain. What’s the motivation for Superman to fight Batman? None. He could just fly away and leave Batman alone. Instead, he pummels Batman until Batman pulls out a kryptonite spear and threatens to kill Superman. Yet without any clear motivation for any of their actions, neither Batman nor Superman’s actions make any sense. As a result, all the fighting they do against each other is emotionally empty and meaningless.
To make motivation emotional, we need to see one character unfairly hurting a second character multiple times. This makes us want to see the villain get defeated in the end.
In “Brooklyn,” an Irish girl leaves Ireland for America. Before she leaves, she’s mistreated multiple times by a nasty woman who runs a shop. By the end, the nasty woman shop keeper has learned a secret about the hero that she wants to use to blackmail the hero. This threat alone makes the hero finally stand up to this nasty woman and explains the rest of her motivation for concluding the end of the movie.
In “The Karate Kid,” the villain has beaten the hero up, taunted him, and then furiously tried to beat the hero up after the hero plays a prank against the villain. This provides plenty of motivation for the hero to finally confront and fight the villain in the end.
In “10 Cloverfield Lane,” the villain seems like a paranoid survivalist nut until the hero learns that something really did happen outside. Then suddenly the villain seems like a nutcase again when the hero learns that he had kidnapped a girl several years ago and held her captive in his underground shelter. After the villain executes another man in his shelter, then the hero (and the audience) fully understands the motivation of the hero to escape the villain by escaping from the shelter.
Motivation is the key to making a story believable and emotionally compelling. Nobody cares about visual action if there’s no emotional motivation behind that action. So make the villain hurt the hero. Then make the villain hurt the hero again and again. Then make the villain threaten the hero in the end.
Once we see the villain unjustly hurting the hero and doing it again, and finally threatening the hero and someone the hero loves, we’re emotionally engaged and rooting for the hero to finally defeat the villain. When your screenplay can make that emotional connection between the audience and the hero fighting the villain, you’re well on your way to writing a good screenplay.