We always for better or worse try to put on paper what's going up on screen - whether we're directing it or not. It's really just an extension of that habit which is trying to tell the reader what the movie will look like. Ultimately that is the job of a screenwriter to a certain extent.
And then at the end of the day, the most important thing is how good are you at risk control. Ninety-percent of any great trader is going to be the risk control.