I was talking to one usability expert and he was describing how they measure task completion. Did the user press the buttons in the right order? Their ideal app resulted in new users completing tasks 100% of the time. This isn’t exploratory learning. You need to be able to fail and explore the possibility space of a particular tool. Through repeated failure and success, users build up robust skills that can be applied successfully in a wide variety of situations.
Well, maybe that's just what you'd expect a game designer to say about application design. Amusing slides anyway. The blog is Lost Garden.