Q. Why did God create the world?
A. Scripture tells us that creation occurred because of the will of God (“… by your will they existed and were created” Rev 4:11b), but why did God "will" (e.g. 'desire') to create in the first place? Herman Bavinck, quoting Augustine, writes, “to the question of why things exist and are as they are, there is no other and deeper answer than that God willed it. If someone should then ask ‘why did God will it?’ he is asking for something that is greater than the will of God, but nothing greater can be found.”
I understand the frustration of these two men regarding this question. We cannot know the full mind of God, and there are important questions that we may never have answered. However, I do think Scripture answers this particular question. 
What is interesting is how Christians have a tendency to answer this question in a self-centered way. Even good and faithful men can fall into this trap. Tertullian, the early church theologian and pastor, once wrote that "God made the world not for himself but for man." Athanasias, the vigorous defender of the doctrine of Christ, said that God "desires all to exist as objects of His loving-kindness." While those statements are true, they do not express the chief purpose for which mankind was created. Today ungodly men make even bolder claims, even going so far as to claim that our happiness and blessing is the main reason for our existence. Bavinck complained that in his day many made “man his own end and all else, including God, only a means” to that end. While America may not have invented the Health-and-Wealth perversion of the Gospel, we have certainly peddled it with unmatched zeal. Don't misunderstand, I firmly believe that God desires our happiness--but there is something that He desires far above that.
The chief purpose of creation—including humanity—is to glorify God. In Isaiah 43:7 God refers to mankind as those “whom I created for my glory, whom I formed and made.” Even the physical creation shares in this praise as “the heavens declare the glory of God (Psalm 19:1). In Romans Paul describes God as the source, means, and purpose of creation, stating that “from him and through him and to him are all things, to him be glory forever” (Romans 11:36). The first principle of our theology and life in God must be to see that His glory is made supreme.
Protagorus, the ancient Greek Philosopher, once said "man is the measure of all things". Sadly, many Christians hold to a way of life that has much more in common with pagan philosophy than biblical revelation.
 Words in italics are from Augustine, De Gen contra Manich I.2. Bavinck, Reformed Dogmatics: vol 2, 430.
 So does Bavinck and Augustine, as they both offered similar answers to what I have provided.
 Tertullian, Against Marcion I, 43; Against Praxeas 5.
 Athanasius, Contra gentes 41.
 Bavinck, Reformed Dogmatics: vol 2, 432.