Is the smoke you smell a result that your house is on fire and you need to get out fast, or is it coming from the food you forgot on the hobs? That fundemental primal part of our reptilian brain also called amygdala doesn't make such judgements, but it just gets us ready to fight back or escape, even before the frontal lobes get a chance to weigh in with their assessment. As long as we are not too upset, our frontal lobes can restore our balance by helping us realise that we are responding to a false alarm and abort the stress response. As we've covered before, our frontal lobes are part of the Neocortex, the newest sections of our brain also defined as the Rational Brain.