By refusing to let others dump their negativity, anger, and resentment on us, we become happier and more successful, both personally and professionally. And when we stop dumping garbage on others, we improve our relationships, strengthen our businesses, and bring our communities together.

Ove, a grumpy, isolated retiree who spends his days enforcing block association rules and visiting his wife's grave, decides to give up on life until an unlikely friendship develops with a boisterous young family that moves in next door.

"Our brain's negativity bias makes evolutionary sense because it kept our ancestors alert to fatal dangers, but it distorts our perspective in today's media environment. The steady barrage of bad news and crisismongering makes us feel helpless and leaves us needlessly fearful and angry. We ignore our many blessings, preferring to heed--and vote for--the voices telling us the world is going to hell. But once we recognize our negativity bias, the rational...