Horse and rider in dressage is like ballroom dance partners, each responsible for it's own balance, moving together in harmony, one leads another. The horse should stand up under the rider, vertical, level and balanced, in self-carriage. The connection is like censoring system that tells the rider how the horse is doing and the aids are signals to tell the horse to change something or not to change something. The aids are not props to hold the horse, legs and reins are not devices to lean on, seat is not to physically displace the horse. A rider must stay vertical and level balancing on a moving horse without disturbing him, tactfully leading him in the gaits, movements, transitions.

The training of the horse requires a rider not to get caught up with end results, doing the movement at any cost, holding the horse together with tight reins and strong bits, physically pushing him around. This is extremely challenging for humans who are very goal oriented, can really focus only on one thing at a time and like to be in control of everything.
Plus, physical aspect of balancing on a moving object brings it's own challenges. Lots of times riders either too stiff, too loose, or trying to move their own body thinking they are moving with their horse. Watching a good rider does not reveal much. They are appear supple, quiet and effective. There is a small visible oscillating movement in their seats. They keep contact but do not pull. Their horses are forward but they are not visibly kicking or shoving them around.

There is so much to understand and learn when it comes to riding effectively. I would like to look into a few aspects which can help us become better riders. These aspects are not often discussed in equestrian literature.

Humans are not designed to ride - humans are designed to walk/run. We are creatures that like to be on the ground, standing firmly on our feet. If ground moves like an earthquake it is very uncomfortable feeling. If we are sitting and the surface we are sitting on moves suddenly we instinctively want to draw ourselves away from that usually seeking support from the ground (hence, pushing into stirrups and leaning forward when a horse bucks or even moves in a weird way like cross canter). Everything inside a beginner tells her/him to get as far as possible from the strange movement under the seat. Humans also catch their balance with their arm movements and upper body movements. This is completely counterproductive to do on a horse! The consequence of all these instincts is inexperienced rider reacts in completely wrong way. Trying to think may not help as that requires time and a rider may not have it. Developing correct instinctual responses takes a lot of practice including practicing staff that is not very pleasant like moderate buck or kick, small spooks, sudden changes of speed initiated by a horse.

Humans are very impatient - this is true not only when it comes to riding/training horses. A very hard thing to do for many riders is to hear small responses from their horses, or giving them time to respond, or taking time and creating very small steps of progress and letting their horse learn at their pace. Examples - a rider asks her/his horse to make a transition from trot to walk, next stride the horse is still trotting a rider pulls the horse to force a transition. Horses with problematic flying changes because they were forced on them.

Humans misunderstand control and pressure when it comes to horses - A few times in my teachings I came across statements from riders that they wanted their horse to respond to light cues so they are not using a whip or spurs. This is very upside down logic. The less tools a rider have to enforce her/his rules the more a horse can push back. A whip and spurs are effective tools, provided a rider uses them correctly without abusing an animal. Many riders shy from a whip, on the other hand kicking hard or constant is OK???... Many riders feel uncoordinated when using a whip so they don't. It is impossible to become better at something without practicing it!
Many riders want to have soft hands so they make their arms limp and give reins away constantly. What they create is jerky, unpleasant contact that encourages head tossing, makes aids ineffective, dulls the horse and gives a bad situation time to unfold because a rider is not ready, reins too long.
Control by holding is also a common occurrence n riding. Holding takes a horse out of partnership. If a rider holds her/his horse in a tight grip to control the speed/pace a rider is doing all the work. A horse is not taught neither balance, nor self-carriage, nor how to go forward properly. Which brings us back to patience, because teaching all of these to a horse things requires enormous amount of focus, patience, skills, practice, time, work, corrections, half halts...

Happy riding...