One of the most daunting and widely repeated insights from recent social research holds, in essence, that your marriage is doomed if you and your spouse can’t muster up five positive interactions for every negative one... ...People don’t generally get pleasure from their central heating, for instance. But they notice when it doesn’t work. Or as Arthur Schopenhauer, the 19th-century German philosopher, put it, “We feel pain, but not painlessness....” ...It is, in fact, our biological nature to accentuate the negative, to dwell on the one cutting remark rather than the three or four sweet nothings. We differentiate between negative...