I find that when I play reality-based characters, it is only as fun for me if I have a lot of time to do research. If I don't it just isn't exciting but if I do, it can be fun because I can learn about that person and the world that they live in and I can become somebody else.
I look at directing as a sporting event. It's a race, a marathon. It's great when it clicks, which is why I push my crews so hard so we can excel.