Eyes are what convey most of someone’s expression. Body language is important, but “eyes don’t lie”. There’s a reason why someone who’s lying will generally try to avoid eye contact. We are biologically set-up to “read” someone’s inner feelings by looking at their eyes.
In storyboarding, if I’m in a real hurry to make a sequence “read” better, I will try to hit the eyes and facial expression as best as I can before anything else, especially if it’s an emotional scene.