Dark Souls, Ni No Kuni and The Witcher 2 were big ones for me. I went into all with pretty high expectations, and none were particularly fun or engrossing, and ultimately I just set them aside.
More recently, I gave up on Pier Solar after getting several hours into it. Maybe it picks up later, but the battle system was alternatively bland and annoying, and the plot and characters followed the same trend. It was a shame too, I was also really hype for that game before it's release. I also recently gave up on The Evil Within. That game was just too uneven to be enjoyable, and I say that as someone who has enjoyed some really shit survival horror games. Lightning Returns was actualy a really hard one to give up on, too, because I ended up really enjoying the first two XIII games. The battle system was awesome - I'd play another game with that combat and class/outfit system in a heartbeat. But christ, the timed aspect was awfully implamented, and if I ever hear Lightning talk about God again I'm going to put my head through a window. Such bad writing @_@.