Why does it seem like less pigment (i.e. lighter colored skin/hair/eyes) is usually considered the ideal? Is t

for instance many people that have dark curly hair, i.e. Hilary Duff and Ashley Tisdale have their hair dyed blond and straightened, as if blond (lighter color) and straight hair were to be more ideal. Likewise, people with brown eyes, i.e. Paris Hilton wear blue contact lenses, as if lighter colored eyes were to be more ideal, and lighter skin is generally embraced over darker skin, although some people think getting a tan will improve the appearance. So why does it seem like less pigment is generally considered the ideal? Also, since there are ways to lighten/darken your hair (with dye) and skin (by tanning/bleaching), is there also a way to actually make your eyes lighter or darker? Like since your skin becomes lighter when you are out of the sun for a long time/darker when you are in the sun for a long time, will shielding your eyes from the sun or exposing them to the sun for some time make them get lighter/darker? Or is there another way to increase/decrease pigment in eyes?