4/24/2014 David Letterman - Neil Patrick Harris on the HIMYM Finale 

“It wasn’t necessarily the happy ending that people were expecting. But Carter and Craig, who were once writers on your show and the executive producers and creators, knew this ending years ago and had played towards that. And I was a big proponent of it and a big fan of it.

Sometimes, people’s growth doesn’t really mean that they grow up. There are certain people who you want them to get into a solid relationship and really settle down and learn from things. And you want Barney to be the guy you can bring your mom home to — but Barney’s the guy who wants to bang your mom.

At the end of the day, it’s not always meant to be that way.”