1) How I Met Your Mother – “Last Forever”
Unlike Dexter, which was clearly going off the deep end before the finale arrived, HIMYM was setting itself up for a strong conclusion. However, it threw all that potential away in what must be one of the most fumbled TV finales ever.
Firstly, running at double the usual length, it is a depressing slog of an episode, which is never a good thing for a comedy show. Still, we might have been able to put up with that if the end result paid off. Instead, various plot threads were torn to shreds rather than being neatly wrapped up. Barney and Robin’s marriage broke up, the titular mother died off-screen and, perhaps most egregiously of all, Ted ran back to his failed relationship with Robin.
“Last Forever” is a terrible reminder that one bad episode is sometimes enough to irrevocably taint a once great show.