I could just let that title stand but I should probably elaborate.
There are many aspects to playwriting, of course, and this is just one of them, but it’s an important one, to do with character. It’s a rule I came up with when writing my first play, that I still find useful to follow:
You have a bunch of clockwork mice. You know how they all behave – maybe some go faster than others, maybe one of them veers to the left, maybe one goes round in circles – and you want them to collide in an interesting way. So you wind them up and put them on a table. YOU CANNOT TOUCH THE MICE ONCE THEY ARE ON THE TABLE.
And that is how playwriting works. You have a bunch of characters and you know how they’ll behave, because that’s what character is: a predisposition to behave in a certain way. You want them to collide in an interesting way in order to create
drama, so you put them in a certain situation. The point is, once a bunch of characters are in a situation you have no control over what happens: the characters will just act the way they would in that situation. So if you don’t like the way a scene is playing out you can either change the characters (make one a little more assertive, or paranoid, or whatever) or change the situation (make one of them arrive earlier, put a bomb under the table, whatever). You cannot change the trajectory of a character once they are in a scene. That’s called
acting out of character. And that is the Clockwork Mice Rule. You can always tell when a writer breaks the Clockwork Mice Rule because suddenly the scene feels implausible, even if the audience can’t work out why.
Don’t touch the mice once they’re on the table.