‘Tarnished for ever’: why don’t great TV shows ever end well?

Line of Duty, Game of Thrones, Lost, Dexter ... so much TV goes from fan favourite to laughing stock the second its finale ends. Has any show ever stuck the landing?

If Sunday night's Line of Duty really was the last ever, there's a sense that the entire programme has been tarnished by its finale.

Because that's what happens with TV shows. Think of Game of Thrones. Think how rapturously it was received for years, and how it was all undone by the abject gormlessness of its final episode. Think of Dexter, and how a once wildly successful series became a laughing stock as the final credits rolled. Think of Lost, and how a divisive finale sent Damon Lindelof into such a funk that his next show ended up being an explicit meditation on the depressive nature of grief. Screw up the landing and the whole thing goes to hell.