Must be youth and high spirits.
...or something like that. It makes my feet hurt just to watch them in 4-inch heels all day! Ugh!
I just finished a great book on the brain. The frontal lobes are the last to develop—and that's where judgment takes place. (I can now use this knowledge to excuse some misspent, youthful events!)
All of that to say, that's why young women wear heels.