One of the chief elements of worship is thanksgiving. Being thankful lies right at the heart of the reason for our existence, because we are created to be in relationship with a gracious God and thankfulness recognizes that relationship.
Thankfulness does not mean being happy that I have something good. It means recognizing the good gift I have received and acknowledging the goodness and benevolence of the one who gave it. Romans 1:21, in discussing the essential nature of sin closely links the refusal to acknowledge God with a lack of thankfulness.
This means that the one who does not believe in God cannot be thankful, because he cannot recognize where his good things have come from. He thinks they just happened through random happenstance or were the result of his own hard work or character. If I give my child some good gift, and he is very happy that he has it and goes off and tells his friends that he bought it himself at the store, is he thankful? Thankfulness requires acknowledging where something comes from.
Directly connected to this truth is the idea that if I am truly thankful to God for the things I have, then I will seek to use those things the way God says to use them. This is because I will always want to use things according to what they are. For instance, if I buy something from a manufacturer then, if I am wise, I will use it the way the manufacturer specifies. Likewise, if the things in the world were given to me by God, then I can only use them the way God specifies, since He is the manufacturer. But if I think the things in the world just happened, then I am the only real judge of how to use them. If I believe that, then the misuse of those things is inevitable, because I will not understand the nature of those things.
Food, drink, clothes, my body, money, relationships, and everything else about this life are all given to me by God. If I am truly thankful, then I will learn to use things the way God teaches. This is why Paul can tell Timothy in 1 Timothy 4:4 that everything God created is good and to be used with thankfulness. Acknowledging God as the source of everything is the first principle that will guide us to its right use.
In our worship, therefore, we have a wonderful opportunity to be trained in thankfulness. We gather together to give thanks to God and acknowledge Him as our creator. We are reminded that our very lives are gifts from God and therefore are to be used in His service. Worshiping God trains us to be true human beings, because the creator / creature relationship defines us, and if we are to have any hope at all of a profitable existence, we must understand the relationship we bear to the God who made us. We are created by God for amazing things, and restored to that purpose from the ruin of sin by the death of Christ. Thankfulness for that creation and restoration will enable us to understand how to rightly use our existence and enjoy the great gift God has given us.