Beauty is only skin deep.
But ugly goes to the bone.
I think it's more along the lines of....
...if they're considered ugly, they work on themselves to make themselves prettier. Whatever make-up, boob job/botox etc... (these days), or whatever they feel they must do. Or in high school they just didn't know any better, or how to apply make-up...whatever.
The pretty ones, they'll know they're pretty and use that to their advantage. They'll drink, smoke and abuse themselves. Every once in awhile one can get by with genetics and stave off the advanced aging of their lifestyle, but usually they turn into the ugly ones if they don't take care of themselves.
