The worst part is, in hindsight the ending makes perfect sense, but that realization then breaks the entire premise of that series in the first place, I actually even liked much of the last season.
Also Barney deserved better, all that subtle development throughout the series that made him a little more awesome than he already was and then at the very end "Hahahaha nope knocked up some girl and my life is fucking shit now for no good reason...I'm awesome"
Lily and Marshall were fantastic pretty much 95% of the time, so I'm glad they didn't get fucked over because they were one of the best examples on TV of a proper couple that don't generally fall into the typical TV tropes that are frankly stupid.