Patricia and Marty Weber were in their walk-in closet one evening, getting dressed for a party, chitchatting about their day, when Ms. Weber made a casual request: "Honey, I really don't want to be there all night. Can we leave after an hour or so?"

Her husband's response? He took off his tie, threw it on the ground and shouted, "Just forget the whole thing! We won't go at all!"

Here's an observation: The most complicated marriages may be those between Innies and Outies—those who like to stay in and those who like to go out. Ask the Webers. He is an extravert. He loves to talk, gather groups of people around him and attend endless brunches, happy hours and networking events. His wife, an introvert, enjoys parties in short doses but prefers to be home reading or spending time with her dog.

Many people believe that introverts, by definition, are shy and extraverts are outgoing. This is incorrect. Introverts and extraverts differ in how they process information. Introverts get their energy internally. Extraverts—spelled that way in psychology circles—gain energy from being with other people, often the more the merrier.

There are shy extraverts and outgoing introverts. Most of us have a little of both in us, but lean one way or the other.