So I love Kurt Vonnegut's Timequake. I'd put it in my top 20 books easily (maybe top 10, but that'd require more thought).
The premise is that the universe contracts a bit and time rewinds. Everyone is thrown back in time and they have to live out their days doing the exact same things they did the first time. They cannot change a single word or gesture. They're unable to.
And I love that idea. A thing I see go around every now and then is a post about how you never know when will be the last time you hug someone or speak to them. But in Timequake, you do. You cannot change what you've said or done, but in that moment, you know. This is it.
It reminds me also of the Borges story about Don Quixote. I forget the title. Anyway, in it, a man re-writes Don Quixote. Every single word is the same, but it is his authorship. And because of that, the book is inherently changed.
In that story, in Timequake, the moments don't change. The picture. The story. The words. None of it changes. Everything is exactly the same. But our perspective is different.
We cannot change the angry words we threw at someone not knowing they were the last ones we'd ever exchange. We cannot change the hard look in our eyes or the sneer on our lips. But we can know and still treasure that moment because it is the last.
Something about that is heartbreaking. Something about is beautiful.