If I have the time, I will sit down with them and just have a conversation with them. These people seem so down and lost in their worlds of pain or depression or whatever, so just talking to them is actually being their best friend.
Other times, I will flash them a smile and say hello. Most people walk by without even looking at who they are walking past. But not me... I say hello and smile at every person I pass.
It's rarely difficult to create happiness. My mission is to spread good feelings, because it always makes me feel good when I leave.
By the way, I'm winning!