A new research study from the London School of Economics found that across gender, income and background, people tend to be the most satisfied in their mid-20s and late 60s. From their mid-20s to mid-50s, life satisfaction declines and hits a low point. Researcher Dr. Hannes Schwandt says this U-shape occurs because people become discontent mid-life because of disappointments at unfulfilled expectations. Does this study hold true in your experience? At what age were you the happiest and why? Is there really a mid-life slump?