What game in your favorite series have you still not finished?

Holy shit! A new game in your favorite series it coming out! Oh, man, you put soooooo many hours into the last one! But then, a few days early, you realize you… never actually beat it. How is that possible? It's one of your favorite franchises and there's still stuff left to be done! This happens to us more times than we care to admit, which has us thinking...

For me? It'd be Pokemon. Yeah, that's right, I haven't caught 'em all. I beat the hell out of some of the old ones, but just never finished Black and White. It was the game that got away, and now it's simply too late to go back. What is your shameful answer? Don't worry, this is a safe place...

What's your example? Be sure to comment with the game, and the reason it slipped through the cracks.