This is the "gold standard" of authentic enjoyment, characterized by the engagement of muscles around the mouth and the eyes (causing crinkling or crow's feet).
A smile is a universal, instinctual human expression used to show joy, connection, friendliness, or even comfort in difficult situations. While often deemed a simple gesture, it is a complex, 43-muscle action that serves as a powerful nonverbal communication tool. 0Smile
A genuine smile that is being repressed to conceal extreme excitement or emotions. This is the "gold standard" of authentic enjoyment,
Smiling triggers chemical reactions that boost your well-being. What's the science behind a smile? - British Council it is a complex
An asymmetrical, sneer-like smile indicating disdain or superiority. 2. Physical and Mental Health Benefits