Alluding to Robert Redford in the early ’70s, director Sydney Pollack once said that “in acting, you have to sense that there’s a reserve somewhere, that you’re seeing the top of the iceberg.”
That, to me, is everything in screen acting — conveying that there’s a lot more underneath than what you’re seeing and hearing in a given scene. Forget technique — if you don’t have the under-the-water iceberg thing, you have nothing.