Think it is subconscious that we take those shots we are comfortable with. Never thought too much about it until it keeps coming up as a topic, and I think we just overthink it.
Even as a youngster hunting, always passed a shot if I had doubts and it just came natural - didn't even think about it. That would be shooting those bullfrogs between the eyes with my Benjaman pellet gun when wading down creeks outside Coyle, Ok. Had to hit just right or they would stay alive, but between the eyes like my father taught me, they float for a few minutes and you can wade out to get'em. If that shot could not be taken, you waited until that ole frog came up in the water again. Same with bow hunting.