Despite being good to great TV for long stretches of time, Lost, How I Met Your Mother, and Dexter have become punchlines because of their terrible series finales. No one’s going to argue that they didn’t suck — especially not George R.R. Martin — but to not watch Lost because of a spotty conclusion is to deprive yourself of “Through the Looking Glass” and “The Constant,” two of the most uniquely fantastic episodes of the 2000s. Occasionally, though, it works the other way. Six Feet Under was consistently solid for five seasons, but the Sia-assisted “Everyone’s Waiting” has become the gold standard by which all other finales are judged. It’s a classic.
Someone on Imgur, via Reddit, put together a chart that shows which finales were good (SFU and Breaking Bad), and which were bombs (True Blood, Enterprise, Desperate Housewives, etc.). The data was collected by visualizing what the average episode rating on IMDb is, then adding a green line (“finale rated higher than average”) or red line (“lower than average”).