In this week's Torah portion we read about the Mitzvah of Bikurim. The commandment to take of your first and choicest fruits of the season and bring them as gifts to the Temple.
A lesson we draw from this is the importance of gratitude in our lives. The importance of giving credit where credit is due, and recognizing that our sustenance doesn't come by our hard work alone, but also, especially, through G-d's kindness and grace.
Being thankful is not only the right thing to do, but it is also good for us, as a thankful person will also be a happier person!