The one preview that always bothers me is PUBLISH OR PERISH since it shows two scenes that aren't in the episode. One where Eddie Kane says he'll be the expert behind every bombing in the world and the other shows Riley Greenleaf giving a salute and saying "Bombs away, Eddie Kane."
I guess originally that they planned to include the scenes but then decided later to take them out. But never adjusted the previews to account for that. That's the only thing I can come up with
Yes, that makes for fun watching! I like the previews, and I'm glad the DVDs have them. It's one of those now-forgotten features of TV shows, like (here I'm not referring to Columbo) the tail-end scene, a sort of one-minute encore that used to be common in comedies. They seemed made to be optional, so they could be removed for more commercials, although once in a while there'd be one that puts a whole new, final twist on the plot. Even the traditional opening theme song seems a relic now, for the most part.