Today at the YMCA I was walking down the hall, looking all brooding and sad (that's naturally how I look when I don't smile XD) when some guy tapped me on the shoulder. He was rather old and visible limping. Wondering what he wanted, I took out an earplug and asked why he stopped me. He just smiled at me and said "Smile, it's free!" and went on his way. I couldn't stop smiling for the next hour.