4) The X-Files
Another show that suffered once it lost one of its leads is The X-Files. The landmark series is rightly remembered as hugely influential in the rise of sci-fi and fantasy shows over the last two decades, but you have to admit that it went on for too long. Far too long.
Any fan will tell you that the heart of the show is the chemistry between David Duchovny’s Fox Mulder and Gillian Anderson’s Dana Scully. It spelled doom for the show, then, when Duchovny bowed out after season seven. Instead, Terminator 2’s Robert Patrick was brought on as Scully’s new partner and the hunt for Mulder became the new big mystery. On the whole, it wasn’t a bad way to deal with the actor’s loss, but there was no real need for it to continue.
3) Dexter
At one time, Dexter was a must-watch show – a fascinating exploration of a killer which just kept getting stronger and stronger. The show’s apex came in the terrific season four which introduced Dexter’s nemesis, John Lithgow as the Trinity Killer.
Sadly, after Dexter pulled out all the stops to make that season so good, it just couldn’t live up to the high standard it had set for itself after that. Instead of bowing out at the top of its game, the show got further and further away from its previous self until it reached its eighth and final season.
The finale, with its now infamous reveal that Dexter became a lumberjack, left fans fuming. Thanks to the downturn in the series, Dexter is remembered as a show that went off the rails rather than for its original brilliance.