While all so-called "standards" of physical beauty are culturally variable and dependent upon the eye of the beholder, most experienced eyelid surgeons agree that the qualities that follow are generally appreciated across many diverse cultures and not solely a matter of Western bias.
An upper eyelid is typically considered more attractive by most people if it lacks excessive skin and fat, possesses a reasonably defined crease (which makes the eye appear bigger -- a universal signal of youth and attention), and displays at least some platform of exposed skin between the crease and the eyelashes (which, in ladies, allows for more effective application of makeup).
A well-contoured lower eyelid free of bulging fat projects an image of youth, energy, and rest.