Self-interest, to be sure, is one of the most important, but we have many other motives - honesty, self-respect, altruism, love, sympathy, faith, sense of duty, solidarity, loyalty, public-spiritedness, patriotism, and so on - that are sometimes even more important than self-seeking as the driver of our behaviors.
Even though I'm an actor, even though I know a little bit about film, I very much view things as an audience member. For me, whether it's TV, film, theater, whatever, it's a big movie, a small movie, whatever it is, I look for the truth in it. I look for the honesty. I just look for if it feels honest and real to me.