I have read opinion (and don't have source at hand) that as horrific as battlefields were it suited human nature well. The clashes lasted minutes (and most batt

I have read opinion (and don't have source at hand) that as horrific as battlefields were it suited human nature well. The clashes lasted minutes (and most battles were series of clashes rather then day long non-stop combat) and even during multi day battles (like Pharsalus or Philippi) there were night breaks etc. Being in constant danger for days (like WW1 trench warfare) is more traumatizing for a human.