Well, it's fairly infamous and obvious, but Mass Effect 3.
It's still one of my favorites but that second disc though...Xenogears....if they only didn't run out of money.
I feel this so muchKOTOR 2 ... Love the games, but the end was so anticlimactic that I didn't even realize it WAS the end until credits started rolling.
Not even just disappointing, but... incredibly stupid too.