Do you buy a game because it has easy achievement or trophies so you can rule the leaderboards?
Or are you a completionist? Someone who doesn't buy a game for the achievements and trophies but does like to get as many as possible.
Or do you totally ignore them and just play the games as if achievements and trophies were never created?
I'm a completionist. I've never bought a game just to get the achievements. I have a few franchise games that I enjoy and aside from a few exceptions I don't buy other games. But the games I do buy, I go for 100% offline Gamerscore, online not so much but sometimes I do that too.
[Edited by SuperSkyline89, 6/20/2010 12:11:34 PM]
The August 2010 issue of PC Gamer has a guest editorial which addresses this somewhat. It's written by Mikail Yazbeck, one of the designers of Mount and Blade: Warband.
He describes what he sees as the proper way of using achievements: as a way to give free-form games the same sense of gratification which linear games have, to get players to play the game longer and in different ways.
However, applied differently, they become the way by which the free-form game becomes linear. They become the designers way of forcing the player to play a certain way.
I think he has an interesting take--it might be worth looking at.
Usually stuff like "clear the coliseum mode" gets you an achievement as well as some cool sword or something. And sometimes games have achievements attached to secret easter egg type stuff, but yeah, those achievements like "you ate a sandwich" are really dumb and I don't see why people feel the need to collect achievements like that.
I take the "it gives me a reason to play longer" approach to it. Before achievements I would finish a game and be done with it. With achievements I play through the game casually to enjoy it and once that's done I see which ones I never got by dumb luck and work towards them.