Slowing down to progress
I work with a lot of horses who have been taught how to evade aids and react quickly to the slightest pressures. People tend to think these horses are "light," which they may be, but this type of lightness does not equate to being balanced and confident. These horses tend to be overreactive and underprepared, making for nervous horses who might act as though they are waiting for the other shoe to drop.
What I often see in this regard are horses who have been taught to quickly respond, to the detriment of their bodies and their balance. We should work to not sacrifice correct movement for the sake of obedience. Horses like this are hard to trust, as they are not actually "with" the aids (which includes the human), and they are often holding a lot of tension.
We’ll always be fighting with horses like this, because they will react quickly to escape undesired pressures from us, but that means they will often respond “wrong” in the human’s eyes. A horse that is disconnected and trying to get relief from us is not one who can really progress in quality training. Progress comes from horses who are confident to think, try, and who understand that our aids are meaningful, and that the purpose of our aids is to guide them into better balance.
I am guilty of all this myself, but I try hard to think about if what I am asking is adding value to the horse and making them more open, supple, and balanced, or if I am taking those things away.
I find it's helpful to ask people to slow down and give them and their horses an opportunity to think about what is being asked, and then help their horse do the thing with better quality. People often feel better themselves when they are able to slow down and guide the horse with fairness and clarity.