This habit is an example of what Chris Noessel calls "One Free Interaction"[1]. Another prominent example is the bounce on iOS scroll views. There seems to be s

This habit is an example of what Chris Noessel calls "One Free Interaction"[1]. Another prominent example is the bounce on iOS scroll views. There seems to be something about being able to fidget with a UI that makes it more comfortable to use. [1] http://www.cooper.com/journal/2009/01/one_free_interaction.html http://www.cooper.com/journal/2009/01/one_free_interaction.h...