City of Heroes, and thus did not alter my playstyle one bit to get them. But when I dove into Lord of the Rings Online, I found that snagging deeds was tied to real rewards (titles, virtues), and I started working through them methodically. In 2008, the dual achievement systems of Warhammer Online and World of Warcraft piqued my interest, and I finally crossed over to the dark side to become an achievement junkie.
There's something about that virtual pat on the back that's so addicting for many. Some people love them for the bragging rights, some because of those usable in-game rewards, and some because it gives them new, game-sanctioned goals to achieve.
So how important are achievements to you? Do you avoid them on principle, or chase after them with all of the restraint of a goofy dog who sees something he really, really must check out right now?