I love things which make people smile. I feel happy when people smile.
When I lived in North America, I used to play a game to make fast food employee smile with my friends. Most of them smiled back when we smiled at them, and some laughed out loud when I did a little coin trick or cracked a joke. It was fun making their hearts smile during their daily routine.
Sam, the guy who created the video above, did a fantastic job to make people smile. I bet they were filled with warm feelings by this prank in the end.