I felt nothing - that was said as if it should end all discussion (although no arguments are ever won or lost on Goodreads) which seems reasonable enough. Isn't that why we read - to feel? But it got me thinking - what exactly do we mean when we say this? It seems to me there are a whole range of ways books can create an emotional response, and many of the endless and tedious arguments about reading are caused by a failure to acknowledge one or more of them.
I've put some very loose and blurry definitions of different types of emotion response to fiction below; no doubt these are biased towards my own reading and writing preferences. Comments, criticism and additions very much welcomed below the line.

This is probably what most people think of when they think of an emotional response to a story: the main character is excited and so you feel a vicarious excitement, the main character is conflicted and hence so are you. Much commercial and YA fiction is written to create just this kind of response, and it seems to me to be the driving force behind the idea that a story should have a POV character that is sympathetic; that there shouldn't be too much of an emotional leap required from the reader.
Much so-called literary fiction claims to be more 'sophisticated' than commercial fiction merely because the character you are invited to emotionally identify with for the duration of the story is unattractive or abnormal in some way: a murderer (The Outsider), a child murderer (Beloved), a child lover (Lolita). And this seems a good thing to me; one of the reasons reading is a valuable activity is precisely because it allows you to emotionally experience the world from someone else's perspective, which may be radically different to your own. And it's the reason I find the commercial insistence that the central character of a story should be someone the reader can easily identify with so dispiriting.

Sometimes the emotional response the reader feels to what a character is going through is conflicting or at odds with what the character themselves would be feeling. Put simplistically, if a chapter about a villain's downfall is told from the villain's point of view, the reader will be experiencing some kind of positive reaction to the villain's own frustration and woe. More interestingly, someone like Jane Austin is great at writing scenes where the characters appear, even to themselves, to be acting civilly and rationally but the reader can perceive the more human and subjective reasons, such as pride (and, um, prejudice) for their behaviour underneath. In Austin's case this doesn't necessarily stop us from also empathising with the characters, but in a book like Carrie it might, at least to an extent. Carrie's actions are in one sense perfectly understandable, and in another monstrous; and the different points of view in the story dramatise this paradox.
3. Atmosphere

Of course, emotions don't have to have anything to do with characters at all; it's an odd fact about writing that almost anything, no matter how inanimate, can be be described emotionally. This is especially important in horror writing, where a sense of dread is frequently achieved by describing everyday locations in such de-familiarising ways that they seem full of portent and threat. Think of the brilliant opening to The Haunting Of Hill House - the sense that something is very wrong about the house is palpable but there is no viewpoint character to be experiencing this; it's all in our heads. And of course this kind of effect is not just limited to fear or tension; a good writer is selecting every detail to evoke whatever mood is desired.
4. The thrill of well-written sentence

"And I said I do, I do.So daddy, I'm finally through [...]If I've killed one man, I've killed two—The vampire who said he was you."
Or if poetry's too much for you on a blurry Saturday morning, how about this from Douglas Adams:
“He turned slowly like a fridge door opening.”
I'm not sure there's much point in trying to explain that - you either get it or you don't. Either feel the rightness of those words in that order, or you don't. Subjective, sure. But as much a part of the reading experience as anything else.
5. Game-playing, Plotting, and Climaxes

More broadly, just knowing a story is nearing its end shapes our emotional responses to what occurs. We don't have to think, for example, about what the events of Romeo &Juliet mean to the poor sods who are left to pick up the pieces in the months and years afterwards because we're already back outside of the theatre, blinking in the light.
6. Intellectual Emotions

I read somewhere that we all belong to one of two camps with regard to facts: those people who think it's only worth knowing something if it's of use, and those who value knowledge for its own sake regardless of its usefulness. The fact that I've remembered this, when it's never been of the slightest use in my life, probably shows what type of person I am.
I think for at least some people the use of intellectual ideas in a piece of fiction triggers a peculiar kind of emotional response, one which is hard to describe (we really should have a specific word for it). Novels like Flatland by Edwin A. Abbot work almost entirely because of this play of intellectual ideas - and that's the best way I can describe it, as "play". Like the music of a piece of poetry, this is one you either get or you don't, I think.
7. Fill In The Blanks

And of course, if what you're after from a book is a likeable hero or heroine with whom you can share their ups and downs, this itch might drive you to close the covers before you finish it. Which is fine; it would be a boring world if we were all the same. But on that principle maybe avoid ranting about how you couldn't relate to the characters at all! on Goodreads. If only because, no arguments are ever won or lost on Goodreads.
8. And Finally, One For The Authors:
That crippling sense of bitter envy and self-doubt when you read something so bloody good it makes any talent of your own seem insignificant and counterfeit in comparison. That.