Like, the specific act of smiling with your mouth open = SUPER feminine/not masculine somehow?
It's the most arbitrary shit, I swear. lol
It was literally just made up out of thin air by chuds desperate to feel manly without actually having to do anything.
It's an easy way to appear sociable in a photo for people who haven't spent time in front of a mirror practicing how to hold a fake smile.
I remember at some point in my twenties when I realized that I would have to actually practice smiling. I also remember a point in my childhood when I always was smiling and people said I was such a happy person. I then remember later how that was no longer the case.