Why is it that negative emotions seem to be magnifiers of negative emotions?  Frustration is a magnifier for frustration, irritation is a magnifier for frustration, etc.  Once one is frustrated over one thing, it’s so much easier for anything else to be frustrating.  Or when one is already irritated, one is more readily irritated.  Why is that?  And why is it that positive emotions don’t seem to work the same way?  Just the old sin nature, I guess.