I'll never forget the first pony I owned. I was 14 years old and had dreamed of having my own horse since I had started riding lessons when I was little. In preparation for my role as someday-horse owner, I kept two stick horses in my closet and pretended it was the barn, and fed my horses "hay" (ripped-up newspaper) twice a day.
So when my parents finally gifted me with Buck, I was absolutely overjoyed. I could finally put all my extensively practiced feeding skills to use. I had a brand new curry comb, an old used western saddle and absolutely no inhibitions (or real knowledge) outside of riding.
I have a pretty bad memory, which is probably a good thing considering that from the bits and pieces I do remember from my years of owning Buck, I was a shitty horse owner. I recall him scraping me off his back under trees bordering the pasture, his frantic pacing of the fenceline when we put him in a pasture by himself (before we got him a donkey for company... I'm horrified thinking about this now) and his often grumpy personality. He blew his belly out when I girthed him up, made me work to catch him and dragged his feet when I tried to get him to trot. At the time, I thought he was just a difficult pony. But looking back now, I realize that he wasn't the problem -- I was. The behavior of domesticated horses reflects the experiences they have with humans - and Buck's behavior was a testament to the fact that I had not yet learned to listen to my horse, to see him as something other than a riding steed and to treat him accordingly. Though I loved him as I had always loved horses, I still had the "riding lesson" mindset - where the bulk of my energy and time was spent on the riding of my horse and not in getting to know him as a sentient being outside of his "job". In fairness, I was young. At that point in my life I was bullish, stubborn, and just wanted to charge down trails on horseback. But the price of that young impulse was a connection with my horse, and his quality of life. No horse wants to just be bossed around and chased around a field. And when those activities are the only thing you do with a horse - well, they learn really quickly that humans, but especially you, are better off avoided. Hence - the avoidance behaviors: running away, bucking, scraping people off on trees, and so on.
It is anthropomorphic to say that horses come to resent us, per se, but it is very easy to see that they learn to avoid things that they don't like. Negative experiences stick in the equine mind longer than positive ones (similarly to how that works in humans) and sadly, many humans repeat the same negative experiences over and over to the point that their horses come to just associate those humans (and sometimes generalize to all humans) with fear, pain, or bullying.
I've seen so many examples of this equine "resentment" in recent years, since committing myself to working with traumatized or other "difficult" horses. My first horse that I owned as an adult, Gracie (RIP), was one of the more extreme examples, having endured terrible neglect and physical trauma. She had subsequently developed a severe habit of biting people who tried to touch her. It took months of gradual desensitization and habituation to eliminate the biting behavior, and a matter of years to truly earn her trust. (You can read more about Gracie here).
My most recent horse, Lilly, is another example. She is a less extreme example, but represents probably the most common form of equine "resentment" seen in paddocks and stables abound. She was nearly impossible for her owner to catch and threw off anyone who tried to ride her. I believe the majority of this behavior was caused by mouth and back pain from the tack that was being used, but her response was also fine-tuned to her learned experience, which was that being caught was generally unpleasant due to the person's somewhat aggressive physical posturing and roughness. (I am not formulating this opinion without knowledge - I did happen to witness Lilly's previous owner interact with her many times).
I have been Lilly's owner for several months now, and though she and I have made great strides together through clicker training and other horse-informed training methods, I still see that old "resentment" rear its head once in a while. As much as I have studied and know about how horses think, I am human and sometimes fall back into my human thinking about what I want to get out of Lilly (which is eventually, to be able to have my son ride her). So, inevitably there will be a week where I get impatient and pack two or three sessions in a row with a bareback pad or bitless bridle. I'm generally successful with these training sessions - clicker training does work wonders. But, I notice a distinct difference in Lilly's body language towards me in the days afterward. No longer eager to be near me, she'll come close enough to see if I have treats and then skedaddle with a sour look on her face. She's smart: she knows from her recent experience that my presence probably equals work and doing things she doesn't want to do.
Of course, you may be thinking, "So what? If we all waited for our horses to want to do things, we'd never be able to do anything with them". Well, there are a few nuances. For one, the horse's personality definitely dictates the individual pace we should take with them. Some horses that were trained early and used to regular work won't need as gradual of a work-up to doing certain tasks, and still seem perfectly happy with their humans regardless of whether they're let out to pasture or lunged for 20 minutes or ridden for 2 hours. So, it's not always as much of an issue for certain horses (though they still deserve some quality time off!). But for the horses like Gracie or Lilly, who haven't been trained consistently and have a hodgepodge history of human contact (as is the case with many backyard horses) - I believe that it's the quality of the connection in combination with well-informed training methods that produce great results, rather than amount of time or repetition. Paradoxically, Lilly responds better to my cues if my proportion of training sessions to "hanging out" sessions is about 1:4. She's less "resentful", meaning less likely to lock herself up or try to escape, and more willing to do what I ask. I liken it to nagging a child: if you constantly ask your kid (or husband, or whoever) to pick up their socks, they're less likely to do it without complaint. It also turns out that Lilly is a lot smarter than I give her credit for: though my early equestrian training in the (ahem) 90's was firmly set upon a foundation of repetition, experience had shown me that horses learn something quite easily after just a few times, over a few days. Too much repetition can actually move your training success in the opposite direction of where you want to be, if your horse learns to dislike your presence or certain visuals and activities. So, it ultimately benefits everyone if we take our time and give our horses reason to enjoy our company.
So, how do we end the sour looks and escape-art ism and get our horses to actually like us? In a word: we have to learn to relax with them. We have to take some time away from the training to just chill out in the paddock or pasture. No goals, no expectations, no stress. When we do train, we need to tailor our methods to the horse's individual personality as well its cognitive ability, in order to maximize results and the horse's satisfaction. But most of all, we have to go back to the little kids we all once were, and remember that the reason we love horses is because of who they are - not just because they're something with 4 legs that can carry us around. If we do that, our horses will feel the difference, and I believe we'll see a big difference in their behavior around us, too.