Good movies/series should avoid these:
-Breaking the fourth wall (this is only good when it helps the illusion rather than breaks it)
Good movies/series should depict the flow of people actually talking to each other, as in depict the difference in language, speaking pattern and awareness.
This does not mean that characters should talk more 'real' like a talk show without scripted lines, it means that there is a difference in the way different people speak.
As an example I will use Wittgensteins concept 'language games':
Language is made up of many small language games, Wittgenstein takes as an example a very simple 'builder language game' where there are two builders, the first one say 'stone', this means that the second one should get a stone to the first one, then the first one says 'hammer', and that means that the second one should get a hammer.
What this example is meant to show is how a word gets it's meaning based on the language game it is used in.
Another example of a simple language game is the teachers language game.
In this game there are two people, a teacher and a student, the teacher says stone and points to a stone or a picture of a stone, the student understands that this does not mean that they should get a stone like the builders game, but that that is called a stone.
What is shown by these two examples is that language have two active parts, speaking and listening (as in interpreting what is said).
So listening is active as the second person in the games have to decide if when the first person says 'stone' what language game is it, should the listener get a stone or should they learn what it is called.
A movie/series should depict difference in language games, as in the conflicts of interpretation of what is being said that come up when two people talk from different language games or experience.
This difference is shown by dialect, body language, word choice and context.