Yet oddly we appear to be going down a route where UI is hidden a lot:
a. long-press on a touch-screen device to select text, show a menu etc.
b. buttons with hieroglyphics to indicate what to do (worse than the old floppy disk for save) - eg. iOS' share button is a box with an arrow going into it (which is confusing to me as I do not want to put my concept into a box - I want to share it OUTSIDE my box of a device).
c. Sliding from sides of the screen to show notification areas, control panels (iOS), or "split screen" apps (Samsung Note), or charms (Windows).
d. Using different gestures to do things like take screenshots on Samsung note devices (swipe your entire hand across the screen)
e. Hiding UI elements until something is done, eg. scrollbars on OSX by default until you scroll (which you would need the scrollbar to actually do...)
They are all very simple once you know them but it must be very difficult as a first-time user, particularly if you are an older first-time user where your ability to absorb information like a sponge is diminished.
Every couple of years interaction is reinvented it seems! This differs from the decades of computer use where the only massive changes were scrollwheels on mice.