Whether you are a writer or an actor or a stage manager, you are trying to express the complications of life through a shared enterprise. That's what theatre was, always. And live performance shares that with an audience in a specific compact: the play is unfinished unless it has an audience, and they are as important as everyone else.
I only tend to think of the week ahead, to keep my eye on the ball and question whether a full stop is in the right place. It's easy to get distracted by the wrong things. If you start thinking of grand gestures, it's going to be a lot of hot air. You have to be logical. The theatre is a very logical place.
My generation of playwrights have grown up writing for studio theatres, and so the task of writing for more than ten or so actors is a huge challenge. Logistically, it's like doing an enormous Sudoku. Making sure everyone is in the right place at the right time in the right order instantly sends me into a cold sweat.