Personal opinion: people prefer not to think of themselves as having a motivation to take the life of another human being - that's a horrible concept to have to realize, to "make real in the mind". We don't like to think about horrible things, and we don't like to think of ourselves as the sort of folks who do horrible things. But each of us is really capable of anything anyone else has done, given the right motivation and circumstances. But our instinct for self preservation protects us from ideas that do violence to our sense of self, so we like to think we would not have participated in the attempted mass extinction of Jews in Europe in the late 'thirties and 'forties. None of us would equate himself to Vlad the Impaler or Stalin. Well, we may not be psychopathic, but like my Grandmother used to say, "You ain' no better'n me, and if you think y'are, I'll KNOCK YA DOWN!!!" And she was right, I'm no better than anyone else. I think we're all pretty much capable of anything. I've seen a lot of people I'd have otherwise thought were pretty decent folks who raped their children, robbed banks, kidnapped people, etc. - a characteristic of the occupation.
And, as J.B.Books, played by John Wayne, said in "The Shootist", "It isn't always being fast, or even accurate that counts; it's being willing. I found out early that most men, regardless of cause or need, aren't willing; they blink an eye or draw a breath before they pull the trigger...I won't."
My notion is that unless you are willing and have a need to kill, you shouldn't even think about the gun, much less make any reference to it or touch it. If you have need to kill, then face that fact squarely, and do your best. If you shoot with a willingness to kill, you will probably be successful in stopping the threat. And if there's no necessity, just calm down and walk away.