The nighttime soap, generally speaking, is the chewing gum on the TV candy shelf. You get a few good, flavorful chews, and taste that hyper-sweet chemical fruit tang from your mouth up to your cheekbones. It’s good and your mouth is happy. And then, too quickly, it becomes a dead thing hanging around on your side and hind teeth, a jaw workout with no life left in its sad, sticky, crushed soul.

“Revenge” is the classic example. The first season, from episode 1 on, was a surge of flavor. The Hamptons melodrama was way over-the-top and entertaining as a result, and Madeleine Stowe’s commanding performance helped a lot. It was classic “guilty pleasure” viewing. But now, in season 2, the story line strains, and the one-dimensionality of the characters is too obvious to ignore. Only a few soaps with that lightning-in-a-bottle mix of characters and plots — I’m thinking of the likes of “Dynasty,” “Dallas,” and “Melrose Place” — actually manage to remain creative, intriguing, and amusing for longer than a season.