I've never understood making this face for a photo. I've always thought it was stupid. That said I barely smile in photos. Much like my ancestors, I've only ever looked terse or laconic in photos.
I have never made a face like this in my life. Maybe I came close getting excited with one of my kids when they were babies, but not full retard like this.
Yeah I make this face at my infant son when I come home from work, because he's a baby and he likes goofy happy faces. I would never make it at an adult.