As some other posters have suggested, the Civilisation series isn't really an addictive game, it can just seem addictive by the method with which you play it - once you start a game you're stuck to the screen until you get bored of that particular map for whatever reason (or you decide to stick it out for a victory), but once the game's off/over you don't really have any emotional attachment to the last map you just left. You just enjoy the process of zoning into a map for a few hours/days solid.
It's a bit like Minesweeper really, but your board is 100,000 by 100,000 rather than 40 by 40. You know, once you make your first click in Minesweeper, you're there until you either explode or have cleared the board, but if you get bored or interupted it's no biggy, you just start a new grid when you're next available.
It's not a story game, in that once you complete it, it's kind-of done bar another complete play-through, it's a time-filler. A game to play when there's nothing better to play or playing a story game requires too much mental investment.
I would compare it to chess, but chess is a completely different game, in that thinking the moves ahead, and remembering them, is utterly crucial in chess, where as in civ you make plans but it doesn't really matter much if you forget or change your intentions. "I was going to build a Library next, nah, actually, I feel like a Lighthouse will be better, nah, maybe another Swordsman for now" etc. And when you do move your pieces it's normally just tech advantage and numbers rather than any specific tactics.
If minesweeper was 100,000 by 100,000 I'm sure it's tag-line would be "Just one more box" Lol
