This is true, I just read a study on it for a course I am taking on the Psychology of Happiness.  Gratitude not only leads to positive affect, it also lowers negative emotions and makes people, on a day-to-day basis, healthier and in an overall better mood and more excited and hopeful for the future.  Gratitude also enhances social bonds / interpersonal relationships, creativity, problem solving, and overall life satisfaction.  Not only that, but it decreases paranoia, fear, and anxiety.  So count your blessings, people! And tell those you love that you appreciate them!

(Source: iloveprettypinkthings)