You probably noticed that all(?) iPhones were presented with kind of triangle on top right or top left corners. Take a look at the official spec from Apple’s site:
It seems that it [triangle in the corner] is a intentionally designed thing. In the real life the phone cracks there. Hence, the slick design is for easier slip from the hands, and the crack area for actual cracking. Take a look below:
Taking into consideration that such feature is visible on all iPhone and iPad specs, I’m warning you to beware of it. Unless you want to get a nice crack.