"You build your heart of plastic, you're cynical and sarcastic, and end up in the corner on your own. 'Cause I love to feel loved, but I can't stand the rejection. I hide behind my jokes as a form of protection." - The Wrong Direction by Passenger
Barney was kind. His greatest fear was people finding this out. But Robin had.
She knew soon after they met, for there had been several occasions where Barney's heart shined through all his pretenses. Robin knew he liked to keep himself guarded. This was obvious through all his plays and his constant need to crack a joke. Barney used these things as armor like Robin used her tough nature and her scotch.
Behind these false walls, Barney had the kindest heart Robin had ever seen. He flew all the way to San Francisco to bring Lily back. He got hit by a bus on his way to make things right with Ted. He drove Robin out to her aunt's farm so that she wouldn't have to say goodbye to her dogs alone.
She would never, Robin thought, understand why he didn't want others to see this side of him.
Robin didn't realize it was for the same reason that she kept her own soft side hidden.
They were both afraid. Her and Barney had damaged hearts. They'd been mangled long ago, back when they were kids, by their fathers. And there had been times that they'd been crushed since.
But eventually they would learn to heal together.