Subject teaching of Confucius' has long been one of my personal norms ever since I was first taught of it.  With adhernce to the belief, I wouldn't indulge myself with essentially "external" things( Smoking is my only addiction, although it may not be that "external".)   As I am aging, now I've almost lost the momentum to try anything new, including the ubiquitous smart phones.

People are now enslaved by that gadget, being engrossed in that small screen almost all the time when they are awake, with the help from fingers of one hand, palm of the other, and a pair of staring eyes.    Standing or sitting in subway cabins or buses, walking on the streets, even attending classes or conferences, smart phone users are so obssessed with their "masters" that they make those "external" stuff the inseparable part of themselves.(Suffering from Obesessive Compulsive Disorder?  Maybe.)  They become distracted by virtual images, alienated from real persons, and oblivious of things surrounding them. 

Don't just tune out, people.  Watch out for moving vehicles or another killing machine like Cheng Jie around you.

P.S. Why don't you reading a pocket book like I do while in subway cabins or on buses ?  Next time I'll tell you a very useful pocket book.