I don't hate Final Fantasy XIII. I think it could have been (and should have been) a lot better, story and game-play wise. In fact, I think XII outshines XIII in some ways - mainly some game-play aspects and definitely more to explore.
Final Fantasy XIII-2 is great game-play wise, but story-wise it is horrible. I feel that it's more a bunch of smaller stories put together, poorly. It was fun in some parts, but... Eh... Overall, I didn't like it. My own personal gripe, little to no fal'Cie involvement. I want fal'Cie!!!