Earlier quoted context omitted.
What made the ending bad in that series? To actually see the women wasn't terrible.. Seinfeld had a bad ending but it doesn't ruin the show.
-- Spoilers below -- There were a lot of things I disliked. The first thing was the marriage of Barney and Robin, which was built up over the last one to two seasons and then undone within 15 minutes (and without good reason!). Overall, the Barney plot of going from married to divorced back to successful playboy to failing playboy to suddenly caring father was really bad (also, he failed as a playboy, but he also had…
First half of S5 and all of S8 and S9 depict in detail why Robin and Barney are horrible together.
>The worst thing, however, was bringing the mother in and then killing her off with basically no screen time. I mean, the whole series was about meeting her!
Nope. The kids themselves tell their father otherwise. Ted tells the story of "how I met your mother" to his kids to justify to himself why he should move on with his life and again pursue a relationship with Robin; his kids tell him that they have no problem with this, and are happy that he is interested in "Aunt Robin", who has already been a substitute mother figure for them (see "Little Boys").
>And what really killed the series for me were the last 15 minutes. I was pretty sad seeing everything that was built up over 9 seasons killed within not even two episodes and then it ends with "just kidding, the whole point of this story was just to date Robin after all".
Rewatch the show. Not just "Little Boys"; every single episode, from the first one onward (which I saw the day it aired, in September 2005), contains clues that lead the patient and observant viewer toward the ending.
Apparently 19 year-old Redditors are not the only ones who believe in TV-style 'shipping "true love", which means that the girl the guy fate says is meant for him in S1E01—in this case, the Mother—must be still The One in S9E22; any variance must be punished. They haven't yet learned that in the real world heartbreak and heartache and sad things do happen, and sometimes it's possible for two lonely old friends to find love again later in life.
To put another way: Most people are lucky to meet the love of their life.
Ted is luckier. He meets two loves of his life.