As more and more people use software UIs in their day to day routines (and as that population starts off using them earlier and earlier in their lives), the trickier it's getting to achieve a balanced, "intuitive" interface in your products.
There is an odd tradition in the UI world to map the physical analog to the digital artifact - to recreate a physical interface for a wholly digital experience. Sounds weird, right? But you see it all the time. Your smartphone probably has some element like this, whether it's the inclusion of an "old style" telephone ring (when was the last time you used an analog telephone that had an actual bell in it?), or some UI element that is trying to be as visually "real" as possible. Do we need an image of an old-school microphone and "analog" VU meter to understand that we can record a voice memo?
Even Apple's Human Interface Guidelines for iOS says that one should "consider adding physicality and realism" to the visual design of your app in order to ease the understanding of the interface. But I'd argue that hearkening back to the physical device that, at one time, was used to perform that same function the computer in your hands is now doing doesn't necessarily make it intuitive. I don't think I've ever used a microphone like the one in that Voice Memo app, and I was a DJ at my college radio station!
This emulation of physical elements that were a necessary part of the original design is what we call a skeumorph and I'm usually against it, especially when it simulates a device most people have never used.
There is much of this type of interface design in the world of audio software, where the physical necessity of modular audio components is mapped 1:1 in the software GUI. Do we need to do it this way or can we strive towards interfaces that get rid of the "chrome" and focus on new ways of interaction? Does it make sense as our software UIs get more and more complex and the feature lists for products are much longer than the original, physical versions? What is intuitive?
Check out this awesome article by Alan Blackwell called The Reification of Metaphor as a Design Tool, which discusses the persistence of metaphor use in human computer interaction. It is a historical analysis of different metaphors over time (there was a 'hey-day' of metaphor use), and the role of metaphors today (when the article was written).