The ancient art of staying out of the way.
Standing in a doorway may seem minor, but it is more than just a pet peeve. It’s a non-verbal message to everyone that you have no business being on set.
Even though Hurry-Up-and-Wait is a way of life in film production, you should never be seen waiting. When you are waiting, that makes the producer unhappy. That makes the director unhappy. And so on. You have two choices: (1) Find something to do, (2) Look busy.
“Standing in the door way” is not just an idiom. Apply this to your entire career – don’t block access to the camera, lights, equipment carts. Avoid talking in a way that makes it difficult for others on set to do their jobs. Don’t make the work day harder for others. Keep that in mind and you’ll make good friends on set.