So after nine years no one grew up. That’s what I can’t get over about the end of How I Met Your Mother. No one grew up.
Even as a fan of the show, I’ve found the final series to be a more of an obligation than a joy but once we met Tracey it really picked up again and, generally speaking, I’m about the same age as the characters and that really helps because, you know, ‘it’s funny cos it’s true’ etc.
Anyway, the punchline was fumbled and in such a way that the rest of the series now has a bad taste about it. Tracey was stuffed in a fridge and How Your Mother Was The Second Most Important Women In My Life is a terrible title.
99.9% Recommended
Clameur Du Cinéma 
I completely felt the same way as you when the finale aired here in the US a few months ago. But even though I much preferred the mother to Robin by the end, I was determined to make peace with how it ended, because I couldn’t possibly hate the ending of my favorite show. So after a couple months of thinking and re-watching, I found new meaning in a lot of the finale. I wrote a fairly lengthy piece about it all here – http://wildamericangooner.com/2014/07/01/making-peace-with-how-i-met-your-mother/ – and I shared it with the creator of the show, Craig Thomas, and with lead actor Josh Radnor. Both of them gave me positive reviews, despite my expressed dislike for the ending. I would suggest giving it a read, as I think it might cause you to see everything a little differently.