[millenia]

Well there are games you never really finish in a first place, like Sims. Or then you finish a scenario or level but there's always more to play like Civilization. There are MMOs and single player RPGs...

But yeah, I don't like to play many adventures at the same time. I might have one unfinished on DS or Xbox while I play something else on PC. But usually if I start another while something is not finished, I end up forgetting too much of the first one and it either stays unfinished or I pick it up again from the beginning a bit later.