The psychologist Paul Rozin, an expert on the psychological experience of disgust, noted that a single cockroach wrecks the appeal of a bowl of cherries but a single cherry will do nothing at all for a bowl of cockroaches!
He points out how the negative trumps the positive in many instances. Bad emotions, bad parents, and bad feedback have more impact than good ones and bad information is processed more thoroughly than good.
We are more motivated to avoid bad, self-definitions than to pursue good ones. Bad impressions and bad stereotypes are quicker to form and more resistant to change than good ones.
John Gottman, an expert in marital relations observed that the long term success of a relationship depends far more on avoiding the negative than on seeking the positive! Gottman estimated that a stable relationship requires that good interactions outnumber bad interactions by at least 5 to 1.