Why is it that human beings are not connected in their sorrows and joys?

Because everyone is an independent individual, we can not break through this layer of obstacles to become someone else, the exchange of ideas can not always be maintained, and because each person is born in a different environment, different insights, interact with different people, his perception of the world is also different, your sadness for him may not be sadness, your joy for him may not be counted as a real joy, so to a large extent, he may be able to sigh or sadness of your experience, but not to empathize with you. So to a large extent, he may be saddened or saddened by your experience, but can not do to empathize with you, even if he went through the same experience with you, but also do not necessarily have your state of mind at that time. So sometimes you can't force others to understand your sadness and happiness, your joy and sorrow, because it is also very painful and difficult for others. But from another aspect, is not also can show that we are ourselves, no one can replace, we experienced the past will eventually achieve different us, ordinary but not ordinary us.