Consider this when you remember the past. Human brains are designed to remember negative, threatening events and the more negative emotional content an event has the stronger the memory and the easier it is to recall. Conversely positive events and emotions have no value to the protective mechanism in the brain and are recorded with less or little neuronal activity...this makes them hard to recall. As an example: if you find $5.00 on the sidewalk you probably forget about it tomorrow. If you get cheated out of $5.00 by a friend you will remember it for a long time. So as we look over the landscape of our lives we tend to see the valleys not the peaks.