Well, to be fair, its true that when someone create something, its never completed, because everytime someone else sees it, it adds their own interpretation to the work.
I don't think that its something bad, because that gives life to the piece.
When there is more than one person working on the piece, is even more open to interpretation, because an actor want to do it this way, a cameraman takes the shot this way, and the illuminator want to give this light. Of course everyone has an script, but at the end every person that works on the piece, adds to it. A current example was Poe Dameron and Finn romance -that there was none, but everyone wanted to be. Why? Because the actors had that chemistry (and they said a lot of times that they would have loved to play romance, for the lulz of it).
As I see it, its inherent to a piece of art to have interpretations. As long as someone interacts with it, it will have a result in their minds. We often call that feedback, when it reach to the creator.