Beauty is in the eye of the beholder. It is only skin deep. It is also a multi-billion dollar industry that thrives on never delivering what it promises and telling beautiful lies.
Is there any truth to claims of antioxidant prowess against aging? Any truth at all to the 8-glasses-of-water myth? Do collagen creams really work?
And that's not even touching on the "new and improved" versions of makeup. I'll grant you that today's powders and mousses and mattes are probably substantially safer than white lead paint in in the Roman days. But I don't think most women would care if tomorrow their makeup were named as the Cause of Cancer--my sex was willing to put poison in their eyes; I wouldn't put it beyond us to suffer cancer as the price we must pay to look good.
The cultural aspects of beauty make for interesting divergences as to what constitutes beauty, but less so, in my opinion, than what constitutes universal features of beauty. There is some speculation that there is a "perfect ratio" of features that beautiful people--or rather, women--possess: large eyes, small chin, clear skin, and so on--pick your favorite supermodel/actress.
However, it is interesting to note that there is no such universal standard for men--there is no psychological equivalent of the "perfect man", the way that there is for women. If you read books from the nineteenth century, authors tend to drivel endlessly about the set of the lips or the shape of the eye. It is especially interesting to note that although heroines are all depicted in more or less the same fashion (clear porcelain skin, liquid eyes of a light hue, gently arched lips), the heroes have a far greater variety in their appearance. Rather, it is their manners and their high "moral code" that makes them desirable.
Which sex has it more difficult? Women, because they must torture themselves to appeal to the fancies of men? Or men, because they must possess the right behaviors to attract the attentions of women?