My first instructor was just very young and I think she was very good naturally and thus she couldnt teach me they whys & hows, only the mechanical "dos" if that makes any sense.
After 20 years away from horses, I started taking lessons at a local barn that was dressage focused and very busy. My experience there was REALLY weird and involved a bunch of instructors who obviously werent aligned very well about expectations.
They placed me with the youngest trainer who was more hunter-jumper. Her method was throwing me on an old grand prix horse and tryingt to get me to "feel" the right way he was moving. I really liked her, but she was often late to lessons everyday. I didnt mind too much, but I had been told it was my job to be tacked up with horse warmed up at lesson start time. So I would be in the arena riding before she got there, since she was often late. Nobody ever said anything, so I figured it was okay.
One day, I messed up and was warming up on a weekend she was offsite at a show, as-I had lost track of what week it was (I felt stupid and flaky). The head trainer sent a boarder down to tell me that she was not there, but that I should practice my flatwork anyways since it was a beautiful day and I was already warmed up. I thought this was a bit odd, but figured I would pay the fee for a ride on a school horse, so begin doing some work.
Then the third trainer came down and started yelling at me to get off the horse, as I should never have been riding it since my instructor wasnt there and yelling at me that I should not be rding the horse at all if she was not on premises. I was like wth is going on here???
I explained what the boarder had said-it turned out the head trainer had not said I should ride the horse,-it was the boarder who had inserted that suggestion, and the head trainer was totally upset I was riding the schooling horse. What was most annoying was the tone the second teacher took-like she was lecturing a child.
Perhaps I have spent too much time in the business world, but the whole thing was so unprofessional, unorganized and poorly done that I left and didnt go back, even though I really liked the first instructor. I was paying too much money to be treated like a "bad little girl" when they are the ones who are don't have thier sh*t together.
I looked around in my area and found a little stable out in the boonies and started taking lessons there from a lady who isnt at all well known. She has pointed out a couple of things in particular about how I ride that have helped me make huge leaps in understanding what is correct.
When I told her this, she said that she wasnt naturally a good rider and had to figure stuff out the hard way herself-thus it makes it easier to explain it to other people when she is teaching. Right now she doesnt have a lot of schooling horses, so I ride this slightly crazed horse who never really was finished out after being raced. We are learning a lot of stuff together, which is normally touted to be a bad thing, but it actually works okay in our scenario given where we are each at in our development.
She is, by far, the best instructor I have had.