2) How I Met Your Mother
By its eighth season, How I Met Your Mother was certainly past its prime, but not quite to the extent of some of the other shows on this list. What damned the series, however, was its disastrous ninth and final season.
Making all 24 episodes of the run take place over Barney and Robin’s wedding weekend meant the plots and laughs were stretched to breaking point. Plus, the whole thing was rendered completely pointless when their relationship was dissolved come the finale.
The big smack in the face for long-term fans, though, was Ted ending up with Robin, a pairing the show had grown out of seasons back. If this had happened after a shorter run, maybe we would have bought it. But after watching the characters grow after so long, it was a pretty poor way to go out.