Duality of the universe

Have you ever wondered why all things have their opposite? 
In philosophical terminology and language
It is called the duality of the universe
Whatever exists in the universe must have opposite
There is heaven and there is hell
There is angel and there is devil
There is light and there is darkness
There is good and there is evil
There is day and there is night
There is rich and there is poor
There is fat and there is thin
There is male and there is female
There is black and there is white
There is tall and there is short
There is beautiful and there is ugly
There is dry and there is wet
There is abundance and there is scarcity
There is wealth and there is poverty
There is young and there is old
There is sunrise and there is sunset
There is good health and there is sickness
There is wisdom and there is foolishness
There is domestic and there is global
There is sluggish and there is energetic
There is monogamy and there is polygamy
There are friends and there are enemies
There are dreamers and there are realists
There are home affairs and there are foreign issues
There are leaders and there are followers
At last, there is birth and there is death