Some TV shows are rapidly evolving organisms. You come back for a new season to find new characters, a new workplace, maybe even a wildly different tone. That can be exciting — though if done wrong, it can strip away what the audience liked in the first place.
Some TV shows offer you roughly the same thing week after week, season after season. There's a danger in that, too, as stagnation can lead to boredom. But there are certain shows that do what they do so well that evolution seems to be beside the point. One of those is Cinemax's "Strike Back," which begins a new season tonight at 10, doing the same things it usually does(*), but with such a high level of execution and glee that I care not a whit about the formulaic nature of it all. A show that kicks this much ass doesn't especially need to stretch.