Spook nailed it.
Ego is the number 1 reason.
If there was no ego...there would be no trying, no "oh I know how to do that", no match stress, no anxiety, no regret....all of that would be replaced by just observing....because there is no good or bad from the result.
And one thing I'd like to add. Just because you are moving fast doesn't mean you have to shoot slow.....I've taken targets at a dead run....as long as you see what you need to see to make the shot, nothing else matters. Tsunami, hurricane, ice storm, sun, rain, fast, slow, easy, hard.....NONE of it matters if you just execute the fundamentals.