Screws fall out all the time, the world's an imperfect place.

xkcd nails it on screws!

In my day job I see a lot of different screws. There are way more screws out there in the wonderful world of mechanical fasteners than Randall Munroe even bothered to depict here, but the reactions to the existence of those other non-Philips or non-flathead (or "straight blade") screws tend to run like this. I don't know how many times in my years at this job it's happened, but if I had a dollar for every time I'd had this conversation:

"Uh, Kelly? I was gonna do this job myself but then I saw the screws and they look like normal screws but they're got this square thing in the head instead of Philips and is that a real thing and do they even make a driver for those?!"

This is when I say "Why yes," and I pull my from pocket my trusty Klein 11-in-1 driver, and for one brief moment, I achieve a status in their eyes that is absolutely Gandalfian or Dumbledoresque.

Now, when I encounter a screw that I do not have a driver for, that's when my command of expletives comes in handy, because really, there's just no need to use a screw that obscure!