As an actor and director myself, I'm constantly wondering what it is that makes some actors "it" and others not.

It's often my job to figure out why a performance is uninteresting and make it more interesting -- mine, or somebody else's. I have a large toolbox of tricks to apply, with varying levels of success.

Yet none of it can ever do what "Stars" do. Even when stars give performances that are mediocre by every measure I know how to apply, they'll be riveting to at least some audiences. You really can see it from the back of a theater, and I have very little idea of how it works.

Not quite none. I do know that it's not at all about the external features, like the spine or the eyes. We don't have anywhere near enough control over that. (Though it is fascinating to work with animators, who do have that level of control over their performances.)

We actors say it comes from being "truthful" in the untruthful circumstances of the theater or the studio, though in the end that doesn't really mean very much. It's just a way of trying to get people to stop doing whatever they're doing consciously and let it happen... whatever the hell it is.