A Circle of Opposites

Good and evil are opposing forces, and you can't really go through life without each one occurring. The evil makes you appreciate the good even more...the good lightens the evil.
Water and fire are the same--they are opposing forces and can't exist in the same space. You also can't go through life without having both. You need water to hydrate you and to cool you down...and fire to warm you and cook your food.
When they come in contact with each other, they create steam.
So, which is good and which is bad? You decide.