SPOILER ALERT YOU FOOL WHY ARE YOU EVEN READING THIS FLEE FLEE FOR YOUR LIFE
I'm seeing a lot of Twitter and blog disgust for the finale to How I Met Your Mother, so I just wanted to get my thoughts about it down before they got all scattered.
Contention: As a series How I Met Your Mother is structurally and narratively sound, and ends the way it needed to end.
First, let's go back to the beginning. How I Met Your Mother (hereforth HIMYM) is a romantic comedy. That's a love story where the main couple gets together at the end of it. And the very first episode established Ted and Robin as the main couple. So, much like on Friends with Ross and Rachel, they were going to get together at the end, Mother or no Mother.
"But aren't Ted and the Mother the main couple?" you ask. No, because narratively that sucks. You're asking the audience to root for two characters to get together where one of them hasn't appeared on the show until the final act. Name me a romantic comedy where that works!
No, it's Ted and Robin, and the point of the show is to get the two of them to a place where they work together. At the start of the series Ted's need is for a grand love story and a stable, loving family, while Robin's need is for a successful career. They might love each other, but the two of them can't meet each other's needs, so the relationship can't work.
HIMYM spends a lot of time getting Ted and The Mother together - of course! - but The Mother is a quirky, enjoyable, and ultimately two-dimensional character. She's Ted's ideal woman, and that's about it. Her purpose in the story is not to be the romantic lead, but to fulfill the needs Ted has that Robin can't meet.
Of course to get Ted and Robin together, that means the Mother has to go. And because Ted's the ultimate romantic, that means she has to die. Which is very Woman in Refrigerators, but a divorce doesn't fit Ted's character and it doesn't meet his needs. The great love stories don't end in divorce. And once Ted's lived the great love story, there's nothing holding him apart from Robin.
As to Robin: the show makes us think that her and Barney work together, but they don't meet each other's needs either. Barney might play the man of the world, but he's a lifetime New Yorker whose needs all come down to his issues with his father. He didn't have a father growing up, so he spends the show consciously wanting a father and unconsciously wanting to be a father, usually expressing that need by appointing himself Ted's mentor. Robin is attractive to Barney as a female "bro", but she doesn't meet his needs.
And Barney certainly doesn't meet Robin's needs. Primarily that's success in her career, but she also has a need for a stable family - something she didn't have growing up. But she can't admit that need to herself, and for most of the show uses The Gang to meet it. It's not until Robin becomes successful and the Gang falls apart that she can admit what she actually wants, and it's at that point that Ted becomes a valid romantic partner for her.
So Ted and Robin get together the only way they could: at 40, when they're both unattached, after they've both met the needs that kept them apart.
Does that make for a good finale? I liked it, for what it's worth. It didn't "wow" me, but it had solid moments and I thought it worked for the show. It certainly topped Seinfeld, and I liked it a lot more than I liked Friends at the end. And if Ted, Robin and Barney didn't work for you, Marshall and Lily remained a solid traditional love story from start to finish.
Overall I think the show's going to be memorable for its humor, its insane timeline and structure, and a hell of a lot of touching moments. And the finale isn't going to ruin that. If you liked it, fine; if you didn't, give it a while and see if it works better on the rewatch. And if you still don't like it, you can never watch it again and the rest of the show will hold up.