What makes phobias so hard to shake? The answer is the negativity bias - or in other words, the power of bad. As John Tierney and Roy F. Baumeister show, we are wired to react to bad over good. It makes sense in evolutionary terms, but in our modern world the lure of bad is, well, bad. It governs people's moods, drives marketing and dominates our news. It can explain everything from why wars start or couples divorce, to why we mess up job interviews or feud with neighbours. But there is good news. By using smart strategies from new science, we can train our brains to get better at spotting our own negativity bias, fighting back with our rational minds to manage the bad in our lives - and even using its power for positive results. Breaking bad's hold over us can help our own lives, at work and in our relationships. Properly understood, bad can be a good thing.