Something I've seen riders I admire do really really well and I try to do as well is set things up so the horse can feel like he's winning, he is a champ, he's successful, he's getting it all right and he's a clever boy. Not in a behavioral sense of oh, make it so it's easy for the horse to do what the human thinks is the right answer, so the human can get what the human wants without a fight ...
But make it so however the horse chooses to respond to something BECOMES the right answer, so the horse can feel like wow, I am so good at this and so clever.
I think this is part of selfless riding cause it's about asking the horse questions about their body, accepting the answer and making sure the horse feels they are doing well, rather than insisting on the rider receiving precisely what the rider wants right now.
I'll give some examples of ways I've put this into practice. I didn't wholly invent any of this, but I’ve morphed it. None of these ideas are perfect and they probably all only work in context - but I hope they all add up to explain the potential selfless riding principle I'm trying to get at.
When I ride green, asymmetrical, unfit and unfamiliar horses they can be wobbly, disorganized and get tired quick. Their shoulder falls one way, or their quarter drifts the other, they look to the inside, they look to the outside, they do a couple congruent steps then they wobble etc etc. Instead of putting those horses on a direction line and trying to keep their posture congruent, I was taught to ride amoeba shapes in the arena. Moving smoothly between changes of direction in response to the horse's posture. So we would flow between straight lines, circles and spirals in both directions in such a way as to make it as easy as possible for a horse. If they started to fall, drift or straighten posturally we would peel off and take them that direction. Then when you get really good you can start predicting where the horse will go posturally next and start asking for the next direction before their posture changes. So everything we asked for was easy and the horse went around the whole time like ‘wow, I have exactly the right posture for this direction. I'm so good at this. What a clever horse I am’. Then we would always stop before they tired and make a huge fuss over them. This is how I introduce myself to horses under saddle.
Another way I was taught to implement this principle is pickup canter in such a place that we could smoothly do a balanced turn either left, or right. And then we would ask for canter, intending a particular canter lead - but if the horse gave us the other lead we wouldn't even blink. We would smoothly peel off in the direction that the horse selected with their lead. So if we were thinking, oh, I'll canter left, then the horse picked up the right lead, we would smoothly canter the horse around to the right. That makes it so the canter lead the horse chose is the right answer, and the horse gets to be right and gets to think they are so clever.
We might eventually try different kinds of aids, spaces, setups and postures etc until we figured out what would cause a horse to naturally pick up the other canter lead - but it would be curious, experimental and it didn't matter if we didn't get a particular lead on a particular day. And it wasn't about teaching the horse their canter leads as much as it was about discovering how to cue that particular horse for a movement they were born knowing how to do. Contrast this method with bringing that horse sharply back to trot for getting the "wrong" lead or trying with stronger aids and more frustration etc ... all that would make the horse wrong. And we were trying to make the horse right and let the horse feel like a winner.
I've been mucking around with this same idea in lateral work. Trying some random small asymmetrical change in my body - maybe moving a seatbone, or a leg, or a hand. The horse responds in some way. Praise. Congratulations, we have discovered a thing! Then just playing around in kind of a casual, curious way - saying "what does this mean to you? Whatcha gonna do if I do this?" And there are no wrong answers. Mucking around while having some general knowledge of common lateral movement aid categories - I can pretty quickly get a horse doing little steps of random lateral movements. Literally just a step or two at a time of something approx. And the whole time however the horse answered the question was the right answer. So again, we developed a language and the horse got to feel like wow, I'm so good at this game!
I’ve also been doing this with my seat and the horses posture - not trying to find some perfect seat or the textbook way to ride every horse, or trying to use my seat to make a particular precise thing happen but mucking around with small changes when riding and noticing how the horse responds in their posture. Different horses seem to appreciate different things on different days.
The last example is a game I used to play as a kid trail riding with my friends. We would go along down a trail and spot some kind of obstacle on the side of the trail - maybe a bank, or a ditch, or some jumble of branches to step over etc. And we would yell "4x4 Pony!" and then steer our pony off the trail to present them at the obstacle. The game had all sorts of rules which we made up and abandoned but all led towards the spirit that 4x4 Ponys were allowed to do or not do the obstacle in whatever freestyle way they pleased. So presenting a pony at a ditch on the side of the trail might mean the pony stepped slowly down into the ditch, or leapt it boldly and trotted off, or ducked their shoulder away and returned to the main trail, or walked a few steps sideways looking at the ground until they found a good spot and crossed the ditch from there. In our childish eyes all iterations of 4x4 Pony were pretty much equally hilarious, except the ones where your mate fell off - those were the very best. Whatever answer the pony came up with was the best answer. Because the obstacles were by very defination "off the road" we never got stuck in front of something trying to get the pony over it. Those ponies got so incredibly confident in themselves. We accidently trained these insanely athletic mountain goat ponies who were always going down the trail with their ears pricked looking for interesting obstacles and it was glorious.
Anyhow I think there is something in there which is an important component of getting along with horses.