Upside down iPhone?

Am I missing something, or will the iPhone not let you use it upside down (dafuq?)? Also, why is there such an abundance of apps that won't go landscape?

Edit:

Cool, thanks for calling me a troll. Maybe I should have prefaced my post with "I love my iPhone, its the best phone I've had, yet I'm curious why it won't do this simple thing..." Which is true. It is the best phone I've owned.

When I want to use the phone upside down: when its plugged in and I want to lean it on something. I use it for recipes sometimes, instructions while trying to fix things, etc. Also, sometimes those extra few inches provided by turning it upside down provide just the right amount of extension to use it in a chair while its plugged in.

Apps I want in landscape: Stuff like The Verge, Facebook, LinkedIn, Appstore.

At least XKCD goes landscape.

The homescreen can stay as is, its easy enough to navigate upside down or sideways.

I just don't understand why apple decided upside down = evil.