Kotor 2: Unfinished Mess.
NWN 2: Crap multiplayer
Fallout NV: Buggy Nightmare.
NEXT!
You do know that the majority of people working for obsidian wrote and developed the original fallout series right?
So lets have some fun.
Kotor2: LA forced Obsidian to release the game ahead of schedual even when the game wasn't done.
NWN2: Atari pushed Obsidian to have the game out early. Despite that, SP was just fine.
FalloutNV: I haven't really seen these earth shattering problems people are going on about.
Then again there's so many hardware configs these days, and not to mention the complete [censored] that people run on their computers. It wouldn't surprise me that people continue to have issues. You know that whole '250 things running the taskbar', along with the '1100 malware infected pieces of junk' running in the background aren't built around having a stable machine.
Now I will say that steam is a pile of steaming [censored] and has caused no shortage of problems.