Frozen
Bert liked to wind her up. He preferred jokes that made her laugh, or, if she was with company, jokes that made her eyes light up, even if she wasn't smiling. Those were the ones that made him feel good too.
Although, he often felt good when he was around her anyway. So, it needn't matter if she did laugh or not, he was simply happy that she was there. But a smile or a laugh certainly made his day a little brighter.
He would make up little dances that she would find amusing, or swing around lampposts. She would chastise him for it, but he could tell she wasn't upset; there would always be a twinkle in her eye.
Mary found it less funny, however, when he pretended that he was going to fall from the edge of a roof. He caught himself last minute, despite the fact that he felt a sharp gust of wind nudging him back into the centre.
"It's only fun an' games, Mary!"
She gave him a look that he swore, even years later, made hell freeze over. And Bert decided that perhaps he wouldn't do that joke again.