I would say the three stages of making a film are the initial 'are we gonna do this,' 'how much will I be paid,' is there a lot of nights, who's it going to be with? The second stage of doing a film is how much fun your going to have doing it. The third stage is was the film a hit?
I think films are about having a good time, so I don't know that there's a message. The message of a film is always what a critic writes, and the fun of a film or the emotion of a film is what the audience feels.
I choose a project based on whether it feels worthwhile working on when it comes to me. But secondly I choose it if it sounds like fun. Projects are determined by just how they strike me at the moment, as they have done throughout my whole life.