And sorry to go off on movies, I know this is books...but I can't restrain myself.
Watch any typical Western movie, and watch the scene where the hero rides into the ranch, canyon, town square, etc. and stops to look around or talk to someone (he's usually searching for the bad guys at this point). Notice how while standing there talking or looking, the rider constantly jerks his horse around in circles, adding an element of excitement to the scene. The horse is never permitted to simply stand quietly while the rider has a conversation, he must fret and pace and be hauled from side to side to keep up the element of energy and anxiety in the film. Arg!!!