"A grateful heart, then, comes through expressing gratitude to our Heavenly Father for His blessings and to those around us for all that they bring into our lives. This requires conscious effort-at least until we have truly learned and cultivated an attitude of gratitude. Often we feel grateful and intend to express our thanks but forget to do so or just don't get around to it. Someone has said that "feeling gratitude and not expressing it is like wrapping a present and not giving it."
--Thomas S. Monson, "The Divine Gift of Gratitude", Ensign, Nov 2010, 87–90