I think one thing that makes Frasier classic are the plot devices, which are in themselves classic—this includes all those zany identity mix-ups, misunderstood conversations, disastrous double entendres, etc. And I think the reason all those oldies-but-goodies work so well is that they mess around so deliciously with two essential things: status and expectation.
Improv comics know all about status—I first read about the concept in this also-classic from the the UK’s Keith Johnstone, Impro (the Brit word for improv). Basically, status is power, and every character has less power or more power, and expectations related to that power. A scene then, in theory, is about pulling power back and forth like a tug-of-war. This tug-of-war is heartily improved by both self-important characters (which describes Frasier and Niles to a tee) and by compromising situations/intentions that are known to the audience but not (all) the protagonists. Hence, why the implied double entendre from my last post, Dr. Crane, your Glockenspiel has sprung to life!, is so funny and effective—because Daphne doesn’t know that Niles intends to seduce her, but we do, and furthermore, we know in this moment that his original expectations have been thwarted. His status is lowered, while Daphne’s is raised—and the upset is highly entertaining.
Of course there are way better examples of this in the show—that one was just handy. Practically every episode starts Fraiser (or Niles) off with a high status, then takes them down notch by pompous notch. Once you start to notice it, it’s fun to follow the ups and downs.
Last but not least—Frasier often messes with audience expectations via the reversal. With the Glockenspiel plot, Niles starts off by desiring Daphne, then switches over to trying to win his own wife back. But when the opportunity arises (using a typical bodice-ripper plot device—trapping the couple together on a stormy night), Niles tries to seduce Daphne, only to find out that he truly loves Maris. The flip-flopping of character wants via plot devices keeps the audience hopping, and it usually ends up messing with character status as well—something, which in the end, can help deepen the character, as in this case, where Niles discovers his truer (and nobler) feelings.
Anyways, that in short, is why I like to think that Frasier is a good diet for a writer’s brain—also a really great excuse to watch TV besides. Hand me that remote!