To start, let's talk about the 80/20 rule. It is a concept that broadly states that the first 80% of a skill takes only 20% of the time/effort to learn. But the last 20% of that skill takes 80% of the time/effort to learn.

So with that concept in mind, let's discuss the general "tiers" of riding lessons. This goes for all sports, but especially for something as intricately mentally complex as riding. There are three tiers of riding lessons.

The WHAT

1) The instructor tells the student WHAT to do.
I.e. heels down, more trot, shoulders back.

This is the most simple and basic type of lesson. Most suitable for beginners because they aren't as capable to be able to handle much more information than this until they get more saddle time to develop more muscle, balance, and ability.

The WHAT and HOW

2) The instructor tells the student WHAT and HOW to do it.
I.e. Ask for more trot by gently closing your calf. Loosen the tension/bracing in the bridle by wiggling the inside fingers.

This is the intermediate level of lesson. Most instructors are capable of doing this, and most riders, once they are past the extreme basics, can use this information well, as they often need the HOW to help start connecting the pieces and do something properly and expediently enough.

The WHAT, HOW, and WHY

3) The highest tier of riding lesson is one where the instructor tells the student WHAT, HOW, and WHY to do something.
I.e. Loosen the tension/bracing in the bridle by wiggling the inside fingers and closing your calf to encourage energy pushing from behind. You need to remove that tension in his neck before you can get him to step up underneath himself with his hind legs. He won't come through with his hind legs because he isn't coming through and rounded in his back. He is hollow-backed because of the bracing in the bridle and neck and because of a lack of energy coming from behind. Once you unlock and disperse the tension in the neck, you and he will start to be able to disperse the tension in the back and start to step up underneath himself more with his hind legs, which will allow him to come through his back 

This is clearly a bit more advanced of a lesson. One in which the rider needs to be open to absorbing all of this information, and one in which the rider has to accept minor incremental changes in a somewhat more "boring" lesson which might focus on something small like this for a larger part of the lesson. 

Clearly this 3rd tier is not only complex, but also shows a requirement of the rider to be able to affect multiple things at once, as there is almost never just one singular "problem" to fix at a time with horses.

Discussion

Some riders find this theory and "WHY" boring. They don't want to learn it, they just want to go jump or go do flying changes. Some riders love learning this theory and intricate detail.

The unfortunate disconnect is that an instructor that teaches at "Tier 3" can oftentimes lose clients because they feel that they aren't progressing fast enough. They want to jump higher, sooner. They want to do more advanced dressage movements NOW. They don't want to get bogged down in smaller, finessed details. So an instructor is sometimes confined to the economic reality of doing what their clients want, because they need to make a living.

But while the student of a Tier 1/2 lesson appears to progress faster initially because they start jumping bigger or performing more advanced movements, in the long term view, the student of a Tier 3 lesson will end up surpassing the Tier 1/2 student because that Tier 1/2 student will hit a plateau that they will not be able to surpass. They will not be able to get by on just sheer desire, they won't have the foundation and finesse to squeeze out the remaining 20% of skill and ability. The Tier 3 instructors will have long-term, successful students who go on to higher levels. The Tier 1/2 instructor will have students who appear to have marginal success at the mid-levels but then never go past that.

The Tier 3 lesson student will just keep flowing and progressing, because they are a true "student of the sport" and have established the foundation and intricate details to continue to master that remaining 20% of riding. They know and trust "The Process" because they are ever-more aware of how intricately detailed the sport is and they know that it takes time and dedication to truly progress in their abilities. 

The penultimate truth is that not all instructors are capable of teaching "Tier 3" lessons. And the final truth is that that is actually okay. Beginners can't handle Tier 3. We need instructors to teach the basics. And aside from that, a large portion of people who take lessons don't actually *want* to learn the WHY. And they never will. So their time and money, and their instructor's time is wasted if they don't view a "Tier 3" lesson as beneficial. You have to *want* to learn those theories. And it's also fine if you don't want to learn the theories. You just have to also accept that there will be a point where you will hit a ceiling and it'll take time and work to backtrack to learn and potentially unlearn some things that you have done in the past, if you want to progress any more.

But if you want to truly learn the WHY, find yourself an instructor who can teach it. Find an instructor who is just as dedicated and curious about the theories and the WHY, because they will be continually educating themselves and able to pass along that knowledge. Unfortunately, sometimes that means switching instructors. But other times it may just mean asking your instructor for more. Maybe they know the WHY but don't freely offer the WHY for a multitude of reasons, like students who have left because they didn't want Tier 3 instruction. Sometimes all you have to do is ask.