In what way does God derive pleasure from us? Philippians 2:13:


  For it is God who is at work in you, both to will and to work for His good pleasure.


I understand that this question deals with infinite concepts and it's impossible for us to comprehend the mind of God as Isaiah 55:8 says:


  For my thoughts are not your thoughts, neither are your ways my ways," declares the LORD.


Nevertheless, I feel I must seek an answer from which to base the purpose of my own actions.  I am looking for opinions from others supported by philosophical reasoning or historical references, not necessarily facts straight from the bible.

This question is in a way asking why god created life at all. I've seen this question answered with a simple "because it pleases him," but that just doesn't seem satisfactory to me.

My hunch is that God created as an extension of his loving nature.  1 John 4:8 says that "God is love", and I know of no other scripture where God is described in such a way.  It's clear to me that this love is referring to a love for others (rather than self-love) so that would be complete with the existence of the Trinity with no call for angels or man.  For this reason, I feel angels and man were created with the intent of us taking part in this love and also showing his love as perfect by redeeming us despite our rebellion. 

As 2 Corinthians 12:9 says:


  And he said unto me, My grace is sufficient for thee: for my strength is made perfect in weakness


TLDR: In what way does our ultimate existence please God?  My tentative theory is that we are used to show his love as perfect and to take part in that love.
I would only speculate from scripture a few simple answers. It is apparent that in Christianity it is important that we identify God as our "Father" through Christ, in fact it is God's will that we know him as our Father through Christ so it is apparent that God wanted children. God is love and he loves his servants the angels but what greater vessel for him to pour his love into than if he were to have children?  The bible says we are heirs of God, so he being a infinitely wealthy king wanted heirs to bless and shower in his dazzling riches. It brings him pleasure to give his children there good pleasure just as a earthly father gets pleasure in his children's delight.

In short God did not just want servants that will worship him, he wanted a family to love and be loved by (of there own free will).