I like to complete the storyline first. That's more important to me (or to any gamer, for that matter), the story of the game itself. We always look for, 'What will unfold next?' That was how games like POP, Resident Evil, and all were build, to look forward to see what would happend next, where the story would take us, what setting, what situation.
Now coming on to achievements. Almost every hardcore gamer looks forward to complete a game cent percent. The reason: the sense of satisfaction, the sense of fulfillment, the sense of achievement, that I could also do so. That's the case with me. When I play a game I always want to complete it cent percent. Sometime I can do it on my own, while other times I have to look for guides or game forums so I could do so. But in the end, when I have done it all, it leaves me satisfied and I enter a relaxed mode, like that of a monk (Did I exaggerate too much?
Perhaps not
).