I think a lot of people are uncomfortable with the idea of an unsmiling photo. There is a mystery about an unsmiling person and that creates tension between the photo and the viewer. I like that tension, I like that mystery.
We've come to expect the smile for personal portraits. Yet an unsmiling portrait can be far more expressive than a grin. There is so much more wonder in the unsmiling photo.
What's happening here? What is he thinking? Is he happy or sad, bored, angry, or just thinking about the next Jurassic Park movie? A hint of a smile, and a whole new level of expression.
Without a smile, we have more questions about the image, we have more expectation. We notice his reflection on the fence next to him. We think he might have a secret.
It is no surprise this handsome boy blosssoms when he shares his smile, but it's an even more pleasant reveal when we experience that smile as a gift, not a thing of the ordinary.