All this talk is a bit of willy waving in my opinion.
You know everyone misses, and its no shame to do so. In fact I would rather any client I am with miss a deer, than wound it. Shooting regularly at a target may give you more experience with a rifle and its feel. Someone may be able to clover leaf a target at 200yds
Now that same person has just walked 5 miles up a Scottish hillside, and crawled 100yds through peat and water to try and shoot a stag, and missed. Or the same person is in a thick wood with falling light and is within 80yds of a grunting Fallow buck, and pulls the shot.
Its called adrenaline. And also bits of paper on a range don't move, and you nice and comfortable taking the shot. There's a world of difference between punching holes in paper and stalking onto deer at times.
The man that says he never missed is either a liar, or hasn't shot many deer in my book.