You can overdo anything.<p>Living in Silicon Valley, I get the impression that teenagers are looking at their phones less than they were five years ago.  A few years ago, I&#x27;d have to dodge people on sidewalks and in store aisles who had completely lost track of their surroundings.  That seems to have stopped.  I see teenagers pull out a phone, interact with it briefly, then put it away.  Also, everybody seems to be in vibrate mode now; I seldom hear a ringtone.