I'm posting this clip from "The King's Speech" to illustrate the importance of acting within a pose.
The scene is taken from early in the story, when the Prince of Wales (Colin Firth) meets Lionel Logue (Geoffrey Rush) for the first time. The Prince suffers from a severe stammer. His wife has sent him to Logue, who specialises in the treatment of speech pathologies.
Overall the characters change their silhouette very little throughout the scene. Instead, they are able to convey information about their inner thoughts with minimal gestures.
A prime example is the final shot. Logue delivers the line "Makes it official, then." but the shot continues for another beat after this. No major change of pose, just a subtle turn of the head, nod and tightening of the mouth that says "I just made a joke, are you with me?"
In an earlier shot, the Prince's self-loathing is made obvious by his nervous fumbling with his cigar case. It's in this scene that we begin to understand the Prince's speech problem may have more to do with his mental state than any physical malady.
I think it's great for us as animators to study live dramatic work like this closely. It helps us to avoid cliches, and gives us more tools with which to tell craft our scenes.