Constant comparison only makes us feel like failures: No matter what, there will always be someone who's at least one step ahead us; and the perfect job, spouse, salary, etc., will always remain elusive.
Elizabeth Weil recently interviewed University of California psychology professor Sonja Lyubomirsky about this phenomenon for The New York Times. In her article, "Happiness Inc.," she writes that, "As Dr. Lyubomirsky has found in her lab (and many of us find around the office or at a bar), unhappy people compare a lot and care about the results."
In a study, "Hedonic consequences of social comparison," Lyubomirsky and her co-author Lee Ross from Stanford University looked at how happy and unhappy people respond differently to feedback, both positive and negative, on a teaching exercise. Happy participants' self-confidence was enhanced by positive feedback, no matter if they also learned that their peers got better results. On the other hand, confidence levels for unhappy people soared when they received positive feedback alone, but only increased minimally when they learned their peers did better.
Via Jim Manske, Marilyn Turkovich