Mental Model vs. Innovation
So I bought an iPod used from a friend. Never has a device been so fulfilling and so annoying at the same time. I love the integration with the $.99-a-tune music store, but: the front panel is too sensitive, there's no on/off switch, there's no volume control (without attaching the additional wired remote do-dad), the wired remote do-dad doesn't have any tactile feedback and doesn't behave predictably - forcing one to refer back to the display, and so on.
I'm trying to love it, or at least make peace with it. Apple clearly produced an innovative product, and yet had to break several mental models to do so (one must hold the 'play' button to turn it off? Reminds me of my old Samsung mobile which one turns on by holding the 'end' key). I suppose designers must reach a point where it becomes difficult to do something better without doing it in a significantly different way ("Think..." (sorry)). Perhaps most people don't notice, already being inundated with so much learning curve with every new device, but I'm a designer and I normally love Apple's products so these quirks drive me insane.