This is the only passage I know of that tells us why God made the world and everything in it. The text says, "God did this so that men would seek him and perhaps reach out for him and find him though he is not far from each one of us." this little verse is packed with interesting items:
1) "Perhaps reach out for him" - the "perhaps" indicates that we do not have to. God is not forcing anyone to reach out to him even though he has built his image in us so that we have a natural inclination to spiritual things. We can ignore him if we want to. God has the power to make us reach out to him but then what does he have? He has those who reach out because they have to. No love, no desire just reaching out to God like an animal, by instinct. Not too satisfying huh? Kind of like telling your husband to tell you he loves you or having to tell him to wish you happy birthday.
2) "Find him" - as if he is hidden? I think the point here is that God is invisible and transcendent. He is not like a tree or a lake he is Spirit ( John 4:24) and "finding" him requires faith. In fact it is only by faith that we can find God. Hence the importance of scripture. God reveals himself there and in nature so that we will reach out AND "he is not far." He is findable.
So, how are we doing in seeking God?
3) Seeking God is left to us. That is our part in having relationship with him. We do not earn anything by seeking him and we cannot find him by being perfect since all have sinned (Romans 3:23). Seeking is our task and Jesus promised if we knocked he would open the door and if we would seek we would fine.