What is the reason behind life and death? Ying and yang? Love and hate?

It is good to be alive you live and then you Die, once you die you are only remembered for who you were by the people that knew you, once they are dead as well was there ever a reason for living other the fact that other peoples lives go on. The fact that one day humans wont exist any more meens that even the famous people wont be remembered. Ying and yang stand for the positive and the negative in life, that takes us to love and hate I think love is positive and hate is negative I have never got on with people that have to much hate in them because there is not much point.I try to love the world and its people as mch as I can that is positive.