I once made a comment on HN about user interface and the advent of touch, in regards to the iPad being great for people who just don't want all that complexity, and a commenter replied to me saying that our parents would then have to learn a completely new user interface paradigm, the touch interface.
My response was that reaching out and touching something that you're interested in is about as intuitive as you can get. Even my kitten 'understands' that if she wants to interact with the sun falling from the sky in Plants vs. Zombies, she just paws at it. She does have a tendency to attack randomly and plant things everywhere, but she's got the basic idea.
A lot of other tech-minded people, however, seem intent on trying to shoehorn the touch interface into their concept of a WIMP UI, then complain when it doesn't work. One coworker, on the day the iPad was announced, even exclaimed 'But it doesn't even have a stylus!', to which seven other people in the department replied 'Good'.