In most bad screenplays, the whole focus is on the hero and all the other characters exist solely to help the hero on his (or her) way. While the hero is the focus, the hero actually changes others around him (or her).
In every screenplay, the hero must change. In every good screenplay, the hero also changes multiple characters in the process. In every great screenplay, the hero changes other characters in similar ways so that they all achieve the same types of goal.
In every script, the hero is searching for a physical goal and an emotional goal. The emotional goal drives the physical goal and the physical goal lets us see whether the hero achieves the emotional goal or not.
For example, in “Up,” the old man’s physical goal is to get his house to the waterfall, but his emotional goal is to discover a new life for himself. In the process of getting his house to the waterfall, he helps Russell, a boy being raised by a single mom. He also helps Doug, the talking dog, who is an outcast among the dogs. In “Up,” the hero and all the other characters are looking for a new life of belonging.
In “Die Hard,” the Bruce Willis character helps restore the confidence of the police officer who thought he could never shoot a gun again after shooting a kid by mistake. In “Die Hard,” the hero and all the other characters are looking to overcome their fears and bring their life back to a happier time in the past.
Ultimately, the hero doesn’t change in isolation but changes others in the process of changing himself. In “WALL-E,” the WALL-E robot gets with Eve but also helps the rogue robots fit in while also getting two humans to meet as a couple.
To make your screenplay deeper and more meaningful, make your hero change and make your hero’s actions change others in similar ways. Audiences might not consciously realize that they’re seeing multiple characters pursuing similar types of goals, but it will ultimately make your entire story more satisfying when multiple characters achieve their goals as a result.