Always Aim for the Head
Everybody knows that the only surefire way to kill a zombie is to destroy the brain, so we always aim for the head, and we’ve already established that you want to be as far away as possible when you do that, so at some point in time you’re going to be shooting zombies in the head. That’s actually one of the only good things about a zombie apocalypse; headshots are awesome! But think about that for a second: Headshots are impressive in movies and video games because they’re the hardest of all possible shots. Taking your time and waiting for the right moment is all well and good if you’re picking off roamers for a disturbing afternoon’s entertainment on a leisurely Sunday picnic, but if shit goes down and you’re faced with a crowd of zombies (they do tend to crowd, you see, quite rude like that) your last concern should be surefire kills, it should be getting the fuck out of there, finding a safe corner to sob in, and then finding a change of pants (in that order).
Yes, headshots are the only way to kill the undead, but not the only way to stop them. A broken leg isn’t just a figure of speech; it’s a fucking leg that is broken. As in, it doesn’t work anymore. Regardless of the level of pain you are capable of registering, a shattered femur or severed spine renders anything essentially immobile. So quickly spraying waist-level fire into an approaching onslaught is a far better idea than lining up headshots for bonus points.
Plus, you’ve got to think: If there’s even the slightest tinge of humanity left in these shambling monsters, a nutshot is still going to at least wind the male ones. There’s a limit to what death can take away; ball-sensitivity might still be in play.