Campaigns or scenarios.

Of course, the campaign is captivating because you don't know what will happen next or how it will all end. But with a scenario, you kind of go through it mechanically, knowing in advance how it will end. Unless, of course, "Island for One" pleasantly surprised me at the end with its unexpected continuation. By the way, I only started playing scenarios when I had nothing else to do, about six months after completing the campaigns.