No, really. I know you come to Scriptwrangler for these brilliant observations. You were probably just wondering what action lines are for, and there: I've answered it for you. Have a great day!
It's pretty shocking how many screenwriters, especially those from a prose background, think that the action lines are where you fill in the reader on all the amazing, intense things going on inside the character's head. To wit:
Beset by sudden and unexpected longing for Jared as the door swings shut, Lucy regrets her plan to make him see the errors of his ways and apologize to her.
What happens on screen? How does the audience know this? I'll point this issue out to a client. And I'll get back something like:
Lucy's face expresses a sudden and unexpected longing that fades under a wave of regret at her plan to make him see the error of his ways. The door swings shut, empty now of Jared.
This is great, except an actor isn't a puppet, and you're not the puppetmaster. This is great except your script is probably about lust and relationships and regret and stuff like that, and you're basically punting here. You're telling the actor how to do their job rather than doing your own.
You've got directors and actors and camera people and lighting people and sound people, and they are all trained to look for the dramatic beats. You don't have to describe each one in intense detail. You need to give them a clear set of instructions that everyone can roughly agree on. Which means the action line should look something like:
Lucy looks up as the door swings shut.
Depending on the context, you may need nothing at all.
We're working on the eighth rough version of Mr. Gary right now, and I'm realizing that I've never talked about one of the biggest reasons action is important.
CUTTING ON ACTION
When you shoot a scene, you probably shoot it from four or five angles. There's a master shot. There are POV (point of view) shots -- say Lucy's and the door's here. There are reverse shots. Cutaways. All this stuff. Editors make hundreds and hundreds of choices when assembling a cut from your footage.
One of the basic rules is that it's best to cut on action. In other words, you don't end a shot just before a character gets up. Make the cut *as* he gets up. That's the most comfortable way for the audience. And it doesn't feel stagnant or choppy. There's not real action to cut on in the first two action lines. Okay, you could probably do it. But there are better ways.
When you include an action, no matter how seemingly insignificant, you're giving the editor a chance to make an aesthetic choice. When they have a clear set of actions, they know what you want. They can work creatively and proactively, rather than covering up problems. When they don't have an action, they can get stuck in a shot
that is less than optimal. Or they have to rely on cutaways, which is another whole can of worms.
And of course, if your actor sucks, you're more or less sunk. If you make a facial expression carry the whole weight of the scene, you're pretty much stuck with the actor's performance.
It would be easy enough to say that a script full of facial expressions is not going to translate as well as a script full of clear action. But realize that it's also an easier film to shoot, act, direct, and edit. It's simply a more feasible project.