Imagine that someone has given you the power to create human beings. So you go about your work diligently, quietly, privately, for as long as it takes to get it right. And, of course, you want your fellow human beings to be as real as possible, as absolutely true as possible, because you're going to be living with them for quite some time. You're going to love them and hate them and worry about them and help them make decisions. And so you build them with flaws, with charms and senses of humor, with personalities that don't necessarily suit your own. You build them knowing forgiveness because you sometimes betray them. The idea isn't to build a better human being, but just to build some who will accompany you, flaws and all, through the next part of your life. And, of course, beautifully flawed is the only way you know human beings to exist anyway.
Now imagine the same someone requires that you devise a machine to kill the people that you've created. And the only rule is that it has to do justice to them according to the laws you chose when you made them. The smart and cocky ones go one way, the quiet-types go another. And so this machine has lots of tiny moving parts, which click and grind against each other, ripping your people up into tiny pieces and maybe even incinerating those pieces so that all that's left when they come out the other end is a charred black smoke which rises away from you and disappears.