A patron comes to the desk and asks where the books on back pain are. I get up to show him, but he says he can find them himself, if I just write down the call number for him. So I write 617.564 on scrap paper and he was off.
A few minutes later he comes back and says he needs help after all. He found the books okay, but it turned out they are all on the bottom shelf and his back hurts too much to bend over.
We have a laugh at the irony, then I pull them all and put them on a cart, so he can take them over to a chair.
This is another example of an unintended side-effect of Dewey, and also the second shelf-height-related incident I've helped with. I wonder how long before we achieve the trifecta - is it possible for books to be too "middle-shelf?"