SPOILER ALERT: 'How I Met Your Mother' finale fires up fans.

Fans are outraged at the final episode of How I Met Your Mother and have taken to social media to express their anger…

There was a running gag on How I Met Your Mother that everyone loved. Even fans of the show who fell out in recent years still found it charming — the slap bet between Marshall and Barney.

Judging by the instant reaction on social media to the comedy’s finale, it was the fans of the show that felt slapped silly by the show’s final moments.

After nine years — nine years — of waiting to hear the story of how Ted Mosby met his children’s mother, the story ended with such an obvious and disappointing blow that blue French horns should forever be outlawed from the planet.

(SPOILER ALERT! Stop reading now if you have not watched the series finale.)

Yes, in the weeks leading up to the finale, there had been plenty of clues that Ted Mosby (Josh Radnor) was telling his kids a story about their deceased mother. But How I Met Your Mother has been known to throw curve balls, and most fans were hoping it was all a trick and that Ted and Tracy, in fact, would grow old together. Not only were we correct that she became ill and died a young mum, How I Met Your Mother went back to its origins story in the final minutes with Ted going after Aunt Robin (Cobie Smulders), with the blessing of his teenage children.

Really? Aunt Robin who married and divorced Barney and has been globetrotting for more than a decade? Ted still has the hots for her? Fans are supposed to still be invested in that story? (Let’s not even go into the fact that the entire season was set in Barney and Robin’s wedding weekend.) And what happened to narrator Bob Saget? We finally got to 2030 and Ted sounds like Radnor—not Saget?

It’s too bad. There was a time when How I Met Your Mother felt inventive and sweet, an innovative throwback, if you will. It was a romantic comedy through and through but its multiple timelines made it fresh and befitting of the Lost era in which it was created. It just went on for too long, and after so many of Ted’s failed attempts at connecting with women, the show stopped connecting with some of its core audience. But enough hung on, and they deserved better than what they got on Monday night.

Was it a complete mess? No. Neil Patrick Harris, the show’s biggest star, had the MVP moment. After Barney divorced Robin and continued to chase women well into his 40s — which in and of itself was a rushed disappointment — he became an unwilling father. When he met that baby girl for the first time, however, Harris owned the moment and if you didn’t get teary, you need to have your tear ducts checked.

“You are the love of my life,” Barney said gazing into his newborn’s eyes. “Everything I have and everything I am is yours forever.”

It. Was. Legen-dary!

Ted’s surprising relationship with Tracy — they had two children before they married — was everything fans of the show could want. The moment of their first meeting also was everything the show has billed it to be. But her sickness and death was dealt with in one fell swoop, and before you could say "Haaaave you met Ted?" there he was in front of his scolding children.

“You made us sit down and listen to this story of how you met Mum yet Mum is hardly in the story,” Penny told her father. “This is a story about how you’re totally in love with Aunt Robin.”

It is? For real? It’s not that the idea of Ted and Robin is horrid. It’s how the show short-changed the story about the mother and got us there that is the problem. After jumping from 2005 to 2030 and many, many years in between, and stalling all season long, How I Met Your Mother crammed its big moment into the last five minutes.

In her toast to Ted and Tracy on their wedding day, Lily (Alyson Hannigan) had called Ted “a man with more emotional endurance that anyone I know.”

The show’s writers took for granted that the audience would match it.

Have you watched the How I Met Your Mother finale? What did you think of it? 

CLICK THROUGH this gallery of cast photos from the show...