3. The X-Files
At a point in the nineties The X-Files was the biggest show on television, Mulder and Scullys continuing investigations of the paranormal drew in millions of viewers who were looking for answers to questions that would could never have been answered in a satisfactory way, but it was a hell of a ride anyway.That was until it got too big for its bridges and everything descended into crapsville. After five seasons of the show someone actually thought that it would be a good idea to make a movie whilst the series was still on the air. This was the beginning of the end as after this point the show began a swift decline that just didn't stop. The questions were either dragged out to an infuriating extent or weren't resolved in a satisfactory way, as the viewers began to lose interest in the show so did the actors, specifically lead man David Duchovny who chose to exit the series in favour of a movie career that never really panned out. In my opinion any show that continues without their main character is flirting with disaster and though things were bad following Mulders departure, they got worse as Gillian Anderson began to appear less and less in the final couple of seasons leading to both Scully and Mulder effectively if not officially being replaced by other agents, one of which was T2 villain Robert Patrick as John Doggett.
Robert Patrick is awesome but he does not belong in the X-Files, while I appreciate the writers attempts to create a different dynamic than that of Mulder and Scully it was a futile attempt to revive a dead horse. Though both Duchovny and Anderson returned to see the series out it wasn't enough to wash away the bad taste that the previous few seasons had left.