ying/yang-opposite or contrary forces yet interconnected and interdependent in the natural world as they interrelate to one another. Many natural dualities are thought of as physical manifestations of the yin-yang concept.
That's a true! Good things and bad things. Life can not live one of these things, but life needs both. Without bad things you never know when is good. ''Bad things happen in life to teach us how to look at good things in a whole new light.