Greater Good Science Center offers a whole lot of data on the benefits of gratitude. In a 2018 paper titled "The Science of Gratitude," they outline the following benefits of a gratitude practice:

increased happiness and positive mood, more satisfaction with life, less materialistic, less likely to experience burnout, better physical health, better sleep, less fatigue, lower levels of cellular inflammation, greater resiliency, and encourages the development of patience, humility, and wisdom

Additionally, every time a person expresses or receives gratitude, dopamine releases in the brain. Dopamine, a neurotransmitter, is produced in two areas of the brain: the substantia nigra and the ventral tegmental. The former has to do with movement and speech, the latter with reward (Carter, 2009). When a person expresses or receives gratitude, dopamine releases, thus making a connection between the behavior and feeling good. The more a person practices gratitude, the more often dopamine releases.

Listen to this week's episode for ways to begin a lifelong practice of gratitude. 

Resources: 

https://ggsc.berkeley.edu/images/uploads/GGSC-JTF_White_Paper-Gratitude-FINAL.pdf