Push-up underpants...

A little over a month ago when I was shopping with my mom we were in an underwear store, and I saw a catalog and was looking at it, and inside there were padded underpands. As if people want a larger butt? Want a larger one enough to buy padded underpants? I thought it was just random in a catalog and it wasn't anything I'd ever see otherwise. It was a crazy idea. But... yesterday when I got home from a long day at the hospital, I flipped on the TV and was suprised to see a commercial for push-up underpants. Like a push-up bra, but for your butt. WHY??? I just don't understand. I mean, I'm not stick thin, but I'm far from overweight, and I like my butt to be curvy enough for some shape, but I don't need any help in that respect. And most women in this country are larger and curvier than I am... so I don't understand why these types of underpants are in demand. What has J-lo done to us? Made us want a bigger butt besides bigger boobs?