These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Anvilicious: Particularly in the later seasons, nearly every episode took on a "cause" of some sort. Whether ghost surgery, advertising alcohol on TV, Drugs Are Bad, or fraternity hazing, there was always some cause-of-the-week that the show tried to hammer home its message about as unsubtly as possible.
It didn't help that Quincy (and in one episode Asten) was not above delivering speeches about the subject.
Seasonal Rot: Quite a few people find the later seasons less enjoyable because of their tendency towards preachiness.
They Wasted a Perfectly Good Plot: "What Happened To Morris Perlmutter?", in which a gripping murder mystery is inexplicably sidelined in favour of a PSA about the title character's hearing for almost the entire episode. (Why yes, this isfrom the final season, how'd you guess?)