(“Presumably other benefits ensue.”)
Have you strolled along a carnival midway and seen the macho game where men are invited to slam a sledge hammer onto a small see-saw mechanism? The blow sends a metal slug shooting up a tall column, the point being to have it ring the bell at the top. A couple of good clangs and the guy wins a stuffed animal for his adoring date. Presumably other benefits ensue.
This is a model for the notion in your horse of thoroughness. You don’t literally clang him to produce it—well, maybe sometimes you have to! I told one rider that although she thought she was using her legs “correctly,” her efforts were like squeezing an old gnarly tube of glue but seeing nothing come out the nipple at the end. You squeeze. You squeeze. You ream out the nozzle with the end of a paperclip. You even roll up the bottom of the tube to press the contents nearer to the spout. Finally, you just have to put that tube on the garage floor and stomp it to get the bead of glue to appear!
A horse which is almost-but-not-quite through is similar to the unyielding tube or the bell which is nearly rung but the rising slug falls short and the bell remains silent.
You’ve heard all those old lines about “close only counts in ______.” This is a time where that is exactly true. This isn’t to belittle good efforts that haven’t yet come to fruition, but until you achieve that last amount of acceptance and connection hiding within your horse, the Music of the Spheres will remain unheard.
In a parallel vein, I once cautioned a student that “a little inattention is the same as a big inattention—only smaller.” The point was that although some incomplete relationships slide by in a test with only nominal “punishment” in the scoring, NOTHING slides by your horse. If you don’t have all of him, you don’t have him enough.