I think this quote from John Wayne in the shootist sums it up pretty well:
John Bernard Books: Sometimes it isn't being fast that counts, or even accurate; but willing. Most men will draw a breath or blink an eye before they shoot. I won't.
I know it's a somewhat different subject, but I've often felt I go into kind of a killer mode when I'm hunting. If I decide I'm going to take an animal, my focus is strictly on making the kill. I don't think much about picking a spot, but I have one picked long before the animal moves into my kill zone. I don't think about it after that, it just happens. I don't think about draw, anchor, aiming...just making the kill. I'm usually kind of surprised when the arrow leaves my bow, to be honest. Once it's on its way, my vision kind of zooms out and I take in the whole picture again.
It is hard to explain in words really, but I think you just have to have that killer instinct mindset. I've missed game for sure, but when I have, I don't think I was in that state of mind. Hope this makes some kind of sense. I do practice quite often, which may be why the shot sequence has just sort of become automatic. Whatever it is, it works for me.