That nagging feeling is urging you to step even deeper into the riding world. Much more awaits aside from just the mechanical steps of the horse. Below the surface level, you discover that you can in fact influence your horse beyond your wildest expectations - you realize that through riding alone, you can create the horse's attitude, comfort, self-confidence, and even the way your horse carries himself. You can affect his coat shine, muscling, the quality of his movement when he is turned out in the field.
You discover that you can be a prime factor in developing his personality.
And at this point, your riding efforts go through a transformation. You now use your technical skill to improve the horse - his way of going and his mental outlook. No longer is it sufficient to get the horse moving from point A to point B. Now, your focus changes to getting there with more balance, a little lighter on the forehand, with more enthusiasm and expression... and you search for the intangibles that become the true essence of riding.
Thus you move from the pure mechanics of riding to a soul-stirring, relationship-creating effort that involves not just a rider and a horse but two partners giving of each self to create a new whole.
This path from the lower-case 'r' to the upper-case 'R' is what keeps you coming back for more....