Visible
Visible is a User Interface term."An interface feature is visible if it either is currently accessible to a human sense organ... or was so recently perceived that it has not yet faded from short-term memory... if an interface forces you to memorize the fact that a feature exists, that feature is invisible. if you are forced to root around the interface until, by luck and perseverance, you reach a sequence of actions that activates a feature, such a feature is not visible."
-Jef Raskin, The Humane Interface
Visibility is tricky. It is certainly desirable, but in large quantities it is often confusing or simply impractical. If every feature in a system is visible, there will be no working room left to the user (except in a very featureless system).
In addition, habituation renders visibility less useful. Thus, visibility is not necessary for an efficient, even (to an extent) friendly interface. But it is very desirable, especially in the case of the new user.
-- seaslug