Why is it that without the expert seeming to do anything at all the very thing you thought impossible happens?
Well, duh. We all know in order to understand the nuances of horse body language, one needs training and experience. The horse has to understand what an aid means and the rider has to be able to be consistent in the application of that aid, as well as the ability to interpret the horse's response.
And, of course, know the secret handshake.
So does the expert know more aids than you? Is that the "secret handshake"? Probably not. What they know is what to expect when a small aid is applied. A really small aid. The kind of small aid that comes from thinking and breathing, from knowing the subtleties of "feel," from knowing the importance of knowing the expected answer to a small request. And that is hard. Really hard. That kind of awareness can only be born through diligent trying, enduring the frustration of failing, and trying again--staying ever-alert for each small flash of ah-ha.
If we try not to make it all happen at once, the horse can become the teacher. He will show us his understanding, and then we can proceed according to that specific understanding, without losing sight of what we want. To lead, to teach, we must look forward and back and inside--simultaneously.
Yeah, it seems ponderous, and there are times when it seems like it would be so much faster to force the issue. But learning to communicate is difficult, and happens in small steps when the parties involved listen to each other. Even if you're the one who has to start listening first. Even if you're the one who has to stay faithful to the small expectations.
That's the secret handshake. And at some point someone will tell you you're magic, and you'll smile and tell them not to give up. The magic takes a while to learn.