Yeah, I hate the ending too, but there's still plenty of game there to enjoy. I'd only return a game if it was unplayable. Same for any entertainment media really. If a book's binding falls to pieces after a few day, or if a DVD won't play, or arrives damaged then yes, I'd take it back. But never because I didn't enjoy the story. Hell, I have a small stack of DVDs I wish I'd never bothered with, but that's my own damn fault.