Futuristic showers.
I’ve read several science fiction novels lately and actually this sin was only committed 1.5 times in the course of three books. Still, I’ve encountered it enough now that it makes me want to hurl a book across the room, then jump and down while yelling at it.
Here’s the thing: Showers actually work pretty well. Water sprays out onto body, body gets clean (add soap in there somewhere). Do we really believe that there is a far better way that technology will find? I don’t. If showering changes, my guess is it will be for the worse, because of lack of energy or fresh water. And that’s okay, that would be interesting, but any time a character in a science fiction novel is luxuriating in a fancy shower with multiple sprays or a weird door or whatever? It’s just gratuitous window-dressing. And it makes me want to kill.
That is all.