Henry shook his head, irritated, "That's not the point. Stop taking me literally." This would read as normal with a full stop after irritated, because it then becomes a beat. Henry shook his head. Irritated, "That's not the point. Stop taking me literally." This reads as if the POV character is "reading" Henry, and deciding from his body language that he's irritated...although he actually isn't - or is? - ...
