This is coming from a HUGE Fallout 3 fan (check my sig, I've had it for years now) and it's more of extreme disappointment than full on rage, but it would have to be Fallout New Vegas. FO3 sure had its' share of problems, but I was always able to either grind through them or figure out a way to mitigate them. I put nearly a 1000 hours, no joke, into 3, so I thought there probably wasn't anything in NV that I couldn't handle. I was wrong. Dead wrong.
Within just a few minutes of starting out, I got my first bad freeze and it only got worse from there. There were slow downs/framerate drops from hell everywhere, but it was the was the freezes, often requiring a hard shut off of my PS3, that were the worst. They happened a LOT and despite trying every trick in the book, from deleting game and eventually all save files, cache cleaning, everything....and nothing worked. So bad that the final DLC, Loathesome Road would just freeze up upon entry into the starting area and was absolutely, positively UNPLAYABLE!
I know some people had decent luck with it, but I was one of the ones that had rotten luck and this was a game that I really enjoyed when it rarely ran. What did piss me off was Bethesda's insistence on Obsidian running that dinosaur Gamebryo engine that deserves to be taken out back and shot like a rabid dog! Then Beth had the balls to announce that they were leaving it still ganked out and moving onto other projects without any more patches. Yeah, screw you tools!
Oh well, taking a breath and /rant....
I, for one, welcome our new feral ghoul overlords! (call me PD -it's easier)