Two people can have lives that seem very similar from the outside. They both can have what seems to be a good life. They have nice homes, plenty of food, a fine family, good jobs. Yet the quality of their lives can be polar opposites. One lacks gratitude. He is always dissatisfied and unhappy. He always focuses on what he considers to be missing. He always has complaints. He creates negativity wherever he goes.
The other has mastered gratitude. He lives a more spiritual life. He is always grateful and joyful. He always has a good word to say about others. He is a pleasure to be around. He is constantly in a state of well-being. He consistently makes others feel good.
(From Rabbi Zelig Pliskin's book: THANK YOU! Gratitude: Formulas, Stories, and Insights: Artscroll Publishers)