When writing your drafts, it can mean don't be afraid of offing characters, even if you really, really love them. Sometimes, it's necessary to move the plot forward. Sometimes, you just need a good murder to build conflict. Sometimes, even though you like the character, that character's really a complete and utter jerk and would only tick off your readers. Nix him. This is the one time when murder's actually legal (oh, and so very therapeutic).
But, even if you take Faulkner's advice, don't delete those words completely. Generally when I write, I have a "dead words" file for each project. Even though a scene or character doesn't work in its current incarnation, it might be perfect for something else down the road. Or maybe it'll never leave that file and stay buried forever. That's okay, too.