Every movie changes you. The process of making a film changes you. You have to be obsessed, you have to get up at 3 in the morning and go "Wait, I have an idea!" You have to continually be drawn over and over again to deepening inside that story, and ruminating over questions: "Why would he say this to her? Why if he was standing there, would she go?" Every one of those answers has to come from some personal place, and in order to do that, you can't sit on the surface. It's such a big change that you can't really explain it to anyone else.