One of the best police shows ever was "Police Story". Instead of making a show about a cop or small group of policemen, "Police Story" did something radical...they made a show about all sorts of different police men and women and their various roles. I love the show and have seen most of them (I can't see them all until they release seasons 4 and 5 on DVD)...including a few on YouTube (like this one). Sadly, however, after 4 1/2 great seasons, the show chose to end with a ridiculous episode...one of the worst of the series.
In an attempt to seem hip and relevant, the producers of the series decided to make one about teens and an undercover cop (David Cassidy) working at the local high school. Now the notion of 28 year-old Cassidy pretending to be 17 or 18 just seemed ridiculous and undermined the entire episode. In fact, a lot of these 'teens' looked amazingly old!! Overall, a rather limp episode and a rather sad ending to a great series...mostly because it just didn't seem the least bit realistic.