The Thalamus feeds into two places simultaneously: The Amygdala
   (the origin of the emotions) and The Prefrontal Cortex It splits
   into two. But it reaches the Amygdala first, everytime. The
   amygdala ALSO feeds into the prefrontal cortex, and the
   prefrontal cortex feeds back into the amygdala afterwards. So -
   pure reason never stands a chance to even exist without emotion.
   You can use your reasoning to control the fear or other
   emotions, but not until you already have the emotion, to some
   degree. Emotions are very powerful; and very complicated. I've
   heard that it's possible that emotions are like the calculator
   of the mind; bringing together all sorts of information - some
   that are conscious and most that is unonscious, and bringing it
   all together and giving you an emotion; that gives you a clue
   how you might wish to react or act.* It's not always correct of
   course; but it's powerful - and can allow us to do things very
   quickly that our rational brain just wouldnt' have time to
   process properly and completely.