Why people are becoming colder to each other?

I have lived in China for over 20 years, and I have been to most of the big cities and many small towns in my country. I always feel that people in my country are cold towards each other, especially in big cities. I feel that everyone is hustling, no matter whether they are on the streets or in the restaurants. There are times when even meeting with your high school classmates, they only exchange some quick greetings and then leave.I once spent a year in Taiwan, I have to say that the island is full of human feelings, people talk to you when you seem to need help on the street; teachers are really kind to students, and I can hardly feel the boundary between us. I got into trouble sometimes when I was traveling alone, and I can not remember how many times I was helped by a stranger. In those times, I felt really moved and felt as if I was living in the real world. But since I have come back, everything is still the same, I feel sad. I love my country, but I hope one day our society will be warmer.

I have had similar feelings in the past.  I did not feel this way in JiLing.  Is was a pleasant place and the people were so warm and friendly.