Good relationships make people happy, and happy people enjoy more and better relationships than unhappy people.... Conflicts in relationships--having an annoying office mate or roommate, or having chronic conflict with your spouse--is one of the surest ways to reduce your happiness. You never adapt to interpersonal conflict; it damages every day, even days when you don't see the other person but ruminate about the conflict nonetheless.

The Happiness Hypothesis: Putting Ancient Wisdom to the Test of Modern Science (ed. Random House, 2015) - ISBN: 9781448166688