Opposite are not always bad.

In Daodejino opposite can contrast, compliment, and sometimes even complete each other. Just as dark and light, one can not fully have a purpose without the other. As dark can happen because their is no light at the time and same the other way. We humans, can not live and survive with only darkness, our food wouldn't grow, so we couldn't have farms, and the greatness sun brings to our bodies, we would be lacking. As same for the light, we humans couldn't survive off of only the sun.  As the same opposite helps the balance of our every day lives. If we didn't have crisis than we would not appreciate the good days. And when we do have hard days we strive to do  better to over come what ever problem.