Sometimes even we are experiencing negativities in life if you look at someone's smile It gives relief, I dont know why but I feel better seeing somone smiling. Like, I have a long tiring day then staring at someone frowning it feels like triple times.
That's why those smiles for others are just little thing but for others that's a big factor. Oww, before I forget. Everyone seems beautiful and handsome when they are smilling. Just keep the smile on your face dont hide it.