I stopped following "How I Met Your Mother," or HIMYM (the necessary shorthand now that it's a popular writing topic), a few years ago. Like many, I could no longer handle the jokes within jokes within jokes (sort of like NBC's "Community" or, of course, Leo Dicaprio's "Inception," but with dreams). Also like most, I never really lost my respect for the show either. Sometimes, I even wondered how it would be if I missed the first seven seasons or so and stopped in for the first time during year eight or nine. Would I be more impressed than I was during the first season? Why, I would wonder, can't these guys settle on a single joke? This is hilarious! Absurd!
It's hard to say exactly what (without writing a really long article), but there was something special about the show and its characters. In addition to marquee actors established before (Alyson Hanigan, Jason Segel, Neil Patrick Harris) and after (Josh Radnor, Cobie Smuders), maybe it was the love story that held fans' interest. We had to know where Ted Mosby's story would end -- and who it would end with. His relationship with Robin was interesting and complex enough to keep us wondering, while Lilly, Barney, and Marshall (and Robin) kept us entertained while we waited. Love sells. By the way, that starting five appeared in 208 straight episodes together, or the equivalent of two and a half NBA seasons.
When Robin turned up for Ted's wedding, some (including me) thought perhaps she and Ted would finally "get it right." They didn't, at least not at that point. Ted married the woman he'd been with most recently, and he never seemed to regret it.
The message of the show would seem to be that it's nearly impossible to marry someone within your inner circle of friends, but obviously that rule was violated early by Lily and Marshall's relationship. Rather, the message, or something close to it, is that some people need to move around for a while before settling down with the person everyone around them believes they should have all along.