Then there are the series that don't seem to know how to end, whether it's the loss of interest on part of the creator or network interference. I don't really remember how that surreal show Get a Life ended. Looking back, the first season seems better than the second. I haven't seen that show in a very long time. Interesting that some of the best seasons of Newhart (where he's the proprietor of a Vermont inn), and The Simpsons, link to Get a Life, due to David Mirkin's involvement. I think he added the nth degree of absurdity.
Also, the original Twin Peakswas better in the first season than the second. I think that was due to David Lynch being involved in some other projects and ABC's meddling. The again, ABC's meddling in a proposed Lynch series with Ann Miller led to the movie Mulholland Drive.