Achievement Unlocked Gah Metagaming, brings the $$ but...
Whoever invented it should be kicked up the ****.
But seriously its fun sometimes, annoying others. Everyone like "ooh I want this achievement, I want that!" <_< then Blizzard had the smart idea of adding it to WoW, oh god. You have any idea how many achievements there are for that game!? Whoever gets all of them would be the god of no life. But least they give you some nice in game rewards, black dragon mount anyone?
Personally I found this rather amusing and simple, the aim is to prance about and do stuff till you work out the achievements, the interesting thing is, they don't tell you what they are, you have to figure them out (unless you cheat :-P) I found it funny and a nice kick in the nutts to all those developers out there who like to milk you for more money by introducing remedial tasks into your gaming, ah games are even more like... household chores then ever before. Fantastic! *sarcastic smile*
And yet people still jump up and down when they get them <_<
Although the ones you get for finishing a game on the hardest setting is good though, you can impress your friends at how awesome you are at beating AI with the brains of a 2 year old... as compared to AI with the brains of a dead animal.