Hmm, if they were of a contrary nature they might create a stultifying impasse, the eventual culmination of which could take the matter completely out of your hands (kind of makes me think of this:
https://en.wikipedia.org/wiki/Titanomachy). Similar to the grinding movement of the Earth's tectonic plates, sooner or later something would have to give, probably in a big way. If complementary, they might just "hit one out of the park" (you know, like a "grand slam," or "beyond your wildest dreams"). I apologize to the world community for the baseball analogies; substitute your own national sports metaphors if you like.