“Girls learn to smile early, and many cultures teach girls explicitly to “put on a pretty face.” It is a way of soothing the people around us, a facial adaptation to the expectation that we put others first, preserve social connections, and hide our disappointment, frustration, anger, or fear. We are expected to be more accommodating and less assertive or dominant. As girls’ smiles become less authentic, so, too, does their understanding of themselves.”