More than smile, actually. My favorite Gloria Vanderbilt quote (Check her out; she is an interesting woman) is this:
“That is the best – to laugh with someone because you think the same things are funny.”
Laughing out loud on your own is usually a rare thing, but laughing with others is delightfully common. Here is a video of a man holding a microphone and an unusual mushroom, who forgets which is which and begins holding the mushroom to his face. When he suddenly realizes what he has done, his uncontrollable laughter made me laugh out loud. View it on your own if you are alone, but do share the laughter with others.