The dream about the library with no books

I keep getting this one where I'm in a library but every shelf is empty, and yet the whole place hums like it's full of conversation. I walk around running my fingers along the spines that aren't there, and somehow I know exactly which book I'd pull if they existed. Weird part is I wake up feeling like I just had the most productive night of my life. Maybe that's what retirement is — knowing the shelves are empty but still hearing the murmur.