My feeling is that tools should be transparent in their use, as in, when you use a hammer to hit a nail, the hammer essentially disappears. And while I think the iPhone of Steve Jobs was like this, I'm pretty sure that Apple intends the trajectory of the iPhone now to be less like a tool and more like an assistant, e.g. it should offer suggestions, preempt your actions, that it should "think for you". It makes it feel like there's a third-party (Apple/Siri) stuck in between me and other people. This feeling has probably crept up gradually enough that most people with smartphones don't notice it, but going from a dumb-phone to smartphone was like being hit with a hammer.