Disagreements do not need to be resolved immediately or before we go to bed. On the contrary. Often, when a fight with our partner escalates, our nervous system goes into overdrive, as we are flooded by currents of rage, hurt, panic and fear. Our muscles tighten, our stomachs clench, our hands begin to tremble. This is our primitive, parasympathetic nervous system in action, preparing us for fight or flight, a state in which we lose our capacity for rational thought.