From “Unforgiven” (imdb):
Little Bill Daggett: Look son, being a good shot, being quick with a pistol, that don’t do no harm, but it don’t mean much next to being cool-headed. A man who will keep his head and not get rattled under fire, like as not, he’ll kill ya.
W.W. Beauchamp: But if the other fella is quicker, and fires first…
Little Bill Daggett: Then he’ll be hurrying, and he’ll miss. Look here…
[stands and draws his gun]
Little Bill Daggett: That’s about as fast as I can draw, and aim, and hit anything more than ten feet away… ‘less it’s a barn.
W.W. Beauchamp: But if he doesn’t miss?
Little Bill Daggett: Then he’ll kill ya.
Little Bill Daggett: Yeah, that’s why there’s so few dangerous men around like old Bob, like me. It ain’t so easy to shoot a man anyhow, especially if the son-of-a-bitch is shootin’ back at you. I mean, that’ll just flat rattle some folks.
Yes it will, Little Bill. Yes it will.