"The test of all happiness," said G.K. Chesterton, "is gratitude." Learning to experience gratitude involves being grateful as an attitude, not as a reaction when good things occur. To be grateful, one does not need to wait until things are perfect. In fact, practicing gratitude makes one receptive to life's blessings, and these blessings continue as we continue to be thankful. In one study, described by author Robert Emmons, participants...