Another example would be the couple in my latest book, And the Devil Will Laugh. Jorge and Paige Hernandez are very similar in some ways, yet vastly different in others. Personality wise, they are worlds apart. Jorge is loud, blunt, abrupt and aggressive whereas his wife Paige is quiet, soft, calm and fair. The two balance each other out in many ways which works in their various scenes together.
When you think about it, real life isn't so different. There is always an energy dynamic.