We've all encountered "misbehaving" horses in our years as riders or owners. But what we consider misbehavior is always an attempt at communication on the part of the horse (even if we don't like or appreciate what they're trying to say). Horses weren't born just to serve humans, and they have feelings and thoughts of their own. While we may think that they're just trying to make our lives difficult, 100% of the time they're trying to tell us something through their bucking, rearing, shying, nipping or other undesirable reaction.
Sometimes they're just trying to say, "I don't want to be ridden. I don't like this". Which, while deemed disobedient, is an altogether natural reaction for animals that didn't evolve in their own societies to be ridden (ever seen a horse riding another horse?). Sometimes they just want to get back to their friends in the barn or in the herd. And oftentimes, though we don't often acknowledge or realize it, the horse is actually experiencing discomfort or pain from the devices we use for restraint (tack).
My horse, Lilly, has demonstrated a prime example of the latter. Her former owner had told me that Lilly had thrown several people off during attempts to ride her, and I just figured she needed some gentle re-training. But at her first dental appointment after I purchased her, the dentist told me that Lilly has what's called "fleshy cheeks", which means that the use of any bit will cause pinching inside the mouth. I had an "aha" moment, recalling the previous owner's rusty old curb bit that I had seen in the tack shed.
The problem with pain is that is a highly effective training method, in that its associative power is so strong that it can be difficult to overcome. Once a horse associates anything in its life with being extremely painful, it is not likely to go near it again. Which is why Lilly is very hard to catch with a halter, and immediately jerks her head away and puts her ears back at the first sight of anything resembling a bridle. She has a similar reaction to saddle pads and saddles, which leads me to believe that she has either had an uncomfortable experience with that equipment as well, or that she associates the equipment with highly unpleasant experiences. In essence, I believe that Lilly threw people off not because she was simply being naughty, but because pain was a major component of her experience in being ridden.
The good thing is, I am aware of why Lilly reacts the way she does, and how to work with her in an alternative way so I don't keep reinforcing her association with tack and pain. But it is going to take a long time to get her to a place where she will even let me place a halter over her head without giving me the runabout and exhibiting some level of stress. Where other people just see a hard-to-catch, difficult horse, I see one that was previously let down by humans that didn't pay attention to all the ways she was trying to say, "Stop, you're hurting me!".
It's our duty as owners, riders, trainers and practitioners to pay attention to the horses in our care when they're "acting up" and ask what the true meaning could be. They communicate in the only way they know how, so it's up to us to listen.