General bitching: I completed the original Doom3 gameplay in the BFG Edition and found out that several things I know I did(Like beating the bosses and beating the bloody game
.) didn't register their achievements. Not the end of the world, I know, but it tend to grate on my nerves(as I have OCD). :\
(While I played it would say achievements disabled even though I never accessed the console[usually this happened when picking up PDAs/vid logs/etc.]. I usually reloaded a previous save and hoped this would allow me to keep getting achievements, but nooooooooo. Dammit Steam, if you're gonna put achievements in games then make sure the system bloody works. 9____9)
I feel your pain :( I also have OCD and something it really catches me on is game achievements, though I'm a little better at walking away from something nowadays when/ if I realise I'm getting too hung up on them. Then again I'm on my fourth now pretty bored playthrough of The Cave at the moment working on the last achievements, so perhaps not that good ;)
For me, the worst about that is that I don't care so much about achievements themselves as a mark of particular gaming skill or pride, it's just that it can annoy me when there's these locked things a game wants you to do alongside all of the already unlocked ones, if that makes sense (I suspect not! :). That can be a perfect trigger for the looped feeling of 'do this, do this' creeping up and taking hold, particularly if it's a game I think I should be able to unlock everything for. Then you find yourself spending hours doing something incredibly pointless and irrelevant until the thing finally unlocks, and the next one, and the next, instead of just enjoying the game :/
Then there's the sod's law that so many times it's the really nasty, nigh-impossible achievements you've wasted too much time on that will go wrong or glitch; you think you've at last got them and then... nooooooooo!!! @##!%!! Such as the first Bioshock's 'Brass Balls' that taunts my otherwise completed achievement list for it...