I'll complete a game, put it away for a while and then probably play it again if I like it. Bioware games are like drugs to me because the story is different each time I play through. Currently finishing ME1 for the 13th time, with DA:O being played 9 times. Also, every time a pokemon game comes out I have to complete it with each starter pokemon. Achievements doing nothing for me, I've never been a completist when it comes to collecting banners in assassins Creed or stuff like that.