I do care about achievements, and sometimes I'm
very tempted to get them all in certain games.
For example, I tried to 100% SR3. After almost falling asleep completing some of the survival missions (killing 800 zombies? WTF, Volition?) I found out that there are Steam-only achievements for beating every mission and activity in coop. After beating the whole game by myself. I always look up achievement guides @ x360achievements, so I didn't notice
Seriously, I don't remember the last time I was so pissed. To be honest, the only reason I didn't unlock them using SAM is because I already talked about it with some IRL friends, and I wouldn't want them to find out I cheated
At least I got the "play coop for 5 hours" one thanks to the sudden influx of randoms asking to join my game after the Humble Bundle...