That is the question. So why not let this question give its own answer?
Everybody knows the 'smileys'. On closer inspection the name is not accurate. A smiley has the corners of its mouth going upward. It does not only smile, it laughs. But let’s drop this.
So how about a dolphin?
Everyone agrees that a dolphin always smiles. But if you look closer you will see that the corners of a dolphin’s mouth are pointing downward. Still it seems as if a dolphin smiles.
How can this be?
The line of the mouth distinctively runs upward from the beginning of the mouth. A good lift for a smile, if not for a hearty laugh. Could it be that the last of the line that curves to the corner of the mouth turns the initially hearty laugh into a smile? That the essence of the dolphin's smile lies in this little end bend?
Meanwhile it has been scientifically established that a dolphin does not smile willfully. That is our human interpretation. Maybe the answer to this question lies in the way that we ourselves distinguish cheerfulness from chagrin.
What strikes me as a man about women is that almost without exception pretty women have the corners of their mouths pointing downward. One could say this hardly adds to their beauty. Maybe this is an evolutionary rarity, originating from the sheer necessity to keep men at a distance. Or that because of all that male attention they have become spoiled bitches. Just guessing.
Could it be that for men, declining corners of the mouth increase the power of female attraction?
But how does this apply to women? We men have flattered ourselves for ages that women beautified themselves for us. Recent understanding suggests, however, that they do this for each other.
Ergo, the male and female take on female beauty results in the same illusion.
And that wraps it up, or so it seems, as also the exception proves the rule:
Yesterevening in the pub, I saw a woman who wore her hair like I used to. A natural beauty, who wasn't concerned about her own loveliness.
But that wasn't what struck me. It was her mouth. Her lips ran up on both sides and ended with poetic accuracy in the little arch that we so intimately adore in the dolphin. Moreover, it moved just like it does in a dolphin.
If I had not beheld this with my own eyes, I would not have believed it.
It is the question that drives us. The answer lies within it.