Happy Vs. Unhappy Research

Research shows that:
"Happy people do not experience one success after another and unhappy people, one failure after another. Instead, surveys show that happy people and unhappy people tend to have had very similar life experiences. The difference is that the average unhappy person spends more than twice as much time thinking about unpleasant events in their lives, while happy people tend to seek and rely upon information that brightens their personal outlook." (Lyubomirsky, 1994)

source: The 100 Simple Secrets of Happy People: What Scientists Have Learned and How You Can Use It by David Niven, Ph.D.