When someone dumps their toxic feelings on us- explodes in anger or threats, shows disgust or contempt-they activate in us circuitry for those very same distressing emotions. Their act has potent neurological consequences, emotions are contagious. We catch strong emotions much as we do a rhinovirus-and so can come down with the emotional equivalent of cold. The speed differential between these two systems- the instant emotional one is several times faster in brain time than the more rational one-allows us to make snap decisions that we might later regret or need to justify. By the time the low road has reacted, sometimes all the high road can do is make the best of things. As the science fiction writer Robert Heinlein wryly wrote- Man is not a rational animal, but a rationalising one.