Yawns are not the only infectious things out there besides germs. Giggles can spread from person to person. So can blushing. But maybe the most powerful infectious thing is the act of speaking the truth.
yeah, sure, the sun will age my skin, and all these giggles and smiles with you will, over time, will crack up my face and give me wrinkles...sunshine, giggles, smiles, you? that's happiness, baby i'm living!