Why do I give a crap if it's intuitive?

A common gripe about Windows 8's UI is that it just isn't intuitive and will involve a steep learning curve.

A common compliment about Windows 8's UI is that it's intuitive and simple to learn.

I, personally, don't give a crap. A reasonable person doesn't judge an experience by how hard it is to learn, but by how productive, how efficient, how gratifying it is to use once it is learned. Not only that, but a UI that I instantly know how to use is a boring one.

What makes an intuitive UI better?