There can be a social hierarchy with horses and from my experience training racehorses we did see a change in attitude many times when a horse won a race. They seem to eat better, look better and not be as fatigued the next day. Bottom line is if a horse likes his job and understands what he is asked to do he will compete to his fullest, either in the show ring or on the racetrack. There is a balance horses must keep between their physical job and their mental state, and if horses are not trained well, unfit to do the task this can create a “bad” attitude toward what your asking them to do. Remember, horses can’t talk so a lot of behavioral issues can be related to soundness issues.