yeah.
i have never bought a game just for achievements, its just an added bonus. Unless you count those burger king games...yeah that was the main reason i got those, but i only had to pay for one since my cousin worked there. Hell i gave up getting em anyway because it wasnt fun to play, and it was tedious.
i borrowed avatar from my bro whom rented it just to get the achievements, it only took a minute to get and i couldnt pass that up.
As for the achievements like collecting flags and stuff....yeah i only did one of those achievements EVER, Crackdown orbs. After that, everytime i see an achievement like it i pass, especially in assassins creed. F that, just F that.
Then theres games like dead rising, you can only get so much fun out of hacking up zombies all day and running against the clock to complete the story, but ive gone back to it several times just to attempt to get some of the more difficult achievements, because the game is still fun but in small doses once you complete it.
Hell i still dont have the saint achievement, because its so damn hard to get every single survivor because you have to base everything off of the time limit and locations, then get them to safety without getting them or yourself killed, then you gotta deal with the unruly survivors who cause problems while they are waiting for the helicopter.
Ill be waiting till i actually feel like doing that one because on top of all that you pretty much have to complete the game again to do it.
They are challenges that add replayability, Like mass effect, Eternal sonata has a few that require more than one play through to get, and replayability of a game thats good enough for it and adds more reasons to play it again is a good thing.
Ive been craving Eternal sonata latley myself, but have not played it again yet.