All of us, whether we realize it or not, desire more joy in our lives. We seek it out and try to hold onto it as long as we can.
However, joy can be elusive, especially when we seek it in material things, hoping that the "next big thing" will give us that joy.
Pope Benedict XVI commented on joy in a homily on the 3rd Sunday of Advent in 2012. He first asks the question of whether or not we can rejoice:
St Paul invites the Christians of Philippi to rejoice in the Lord. Can we rejoice? And why should we rejoice? St. Paul answers: because “the Lord is at hand” (Phil 4:5). In a few days we shall be celebrating Christmas, the Feast of the coming of God who made himself a child and our brother so as to be with us and to share in our human condition. We must rejoice in his closeness, in his presence, and must seek ever better to understand that he really is close, and thus be penetrated by the reality of God’s goodness, joy at Christ being with us.
Joy must first of all spring from a realization that God is with us. Our joy must be rooted in the Lord and his presence.
Benedict XVI continued in his homily on the topic of joy, exploring true and lasting joy must be received from God with a grateful heart:
The joy the Lord communicates to us must encounter grateful love in us. Indeed, our joy is complete when we recognize his mercy, when we become attentive to the signs of his goodness, if we truly perceive that this goodness of God is with us and thank him for all that we receive from him every day. Those who selfishly welcome God’s gifts fail to find true joy; but the hearts of those who make God’s gifts an opportunity to love him with sincere gratitude and to communicate his love to others, are truly filled with joy. Let us remember that!
True joy has nothing to do with a selfish heart, but a heart open to God's gifts, ready and willing to share those gifts with others.
If you want to experience lasting joy in this life, you must live generously and thank God every day for those gifts he has given to you.