When How I Met Your Mother premiered in September 2005, it had been 16 1/2 months since the series finale of Friends and just about a year since the startlingly successful debut of LOST.
The real legacy of How I Met Your Mother, though, may be as the most successful LOST clone ever produced — for both good and ill, as the sharply divided (and deeply felt, on both sides of the argument) reactions to the series finale suggest.
Obviously, the stories LOST and How I Met Your Mother could scarcely be much different (give or take a Jorge Garcia guest appearance). LOST was a global-scale, sci fi-tinged drama that posed questions about the very nature of our existence and our purpose in life. HIMYM took place largely inside a bar and an apartment upstairs and was concerned with five people and their love lives.
But the way creators Carter Bays and Craig Thomas constructed and told the story of How I Met Your Mother makes the show a direct descendant of LOST, whether intentional or not. The 2005-06 season featured three sci-fi shows greenlit in the wake of LOST's success the previous season. None of them, including CBS' Threshold, lasted longer than a season.
It went largely uncommented on at the time, but HIMYM was employing a lot of the same tactics that helped LOST stand out — flashbacks and -forwards, a sometimes unreliable narrator and a stories that looped back on themselves. More than any live-action comedy in recent memory, it rewarded close viewing and sustained viewing with call-back stories and jokes, and it tied off most* of the dangling plot threads by the end of the show’s run.
(*Even here, there’s a parallel: “What about the pineapple?” is the HIMYM equivalent of LOST's “Who was in the outrigger?,” although it's implied there will be an answer to the pineapple question on the final-season DVD set.)
Bays and Thomas said repeatedly in interviews, the show knew its endpoint fairly early on. Well, we can see how that worked out. As HitFix’s Alan Sepinwall pointed out in his review of the HIMYM finale, part of the ire over LOST and some other finales stemmed from the fact that those shows’ creators admitted they were making things up as they went along and adapting to ideas and actors that weren’t there in the beginning. Those who didn’t enjoy the HIMYM finale now have a counter-argument: Becoming beholden to a plan you laid out when you thought your show might not last more than a couple of years can prove just as problematic when your show ends up growing and changing for seven more.