Highly emotional experiences in the past are often remembered. As experiences they may have been Good, Bad or Ugly (just like a Clint Eastwood movie). Here's the thing... What most people don't know is that when they think about a highly charged emotional experience, the brain will fire in the exact sequences and patterns as before. They are firing and wiring their brains to the past by reinforcing those circuits into evermore hard wired networks. They also duplicate the same chemicals in their brain and body as if they were experiencing that same event in the moment. Those chemicals begin to train the body to further memorize that emotion. So the "take away" is to be cautious about what you repeatedly recall and ruminate over. Remember the good. Because of the biochemistry involved with the brain's Neuroplasticity, attempting to change emotional patterns can feel like drug withdrawal. We can actually be addicted to our chronic negative moods!!! Neurons that fire together, wire together. Unlearning negative patterns must first happen before learning new positive patterns.