We tend to think of extremes of emotions as registering, for example, you have to cry or laugh or get angry. But for the most part, we find it difficult to read each other most of the time. If you walk through the street, most people are pretty difficult to read. But they're thinking inside.
When you're still, and some actors are really brilliant at that, you bring a kind of energy to you as opposed to sending the energy out. There are some actors, like Gary Cooper or Kevin Spacey, that are absolutely brilliant - Gene Hackman is another - at being and allowing the audience to just do the work.