You absolutely know couples like this. There are two types of people in the world: type A and type B. Or so common wisdom says, anyway — of course, as with anything human, we’re all much more complex than that. Still, sorting people into type A and type B categories can sometimes serve as useful shorthand for understanding ourselves and others. This is especially true in romantic relationships. You might think that a partnership between a type A person and a type B person could never work, or