This Sunday is Trinity Sunday, which means it's a
Sunday set aside to celebrate the doctrine of God
The idea of the Trinity developed over centuries of debate revolving around the scriptural witness, the experience of believers and the traditional interpretations handed down by Jesus' disciples. There's also probably more than a touch of Greek philosophy thrown in as well, those old church dudes (and they were mostly male) loved their Greek philosophy. In some ways, the development of the doctrine of the Trinity resembles a group of grumpy blind men trying to create a Renoir painting - lots of arguing over things that can't really be understood. All analogies fall short eventually because they're, well, analogies - not descriptive reality. And there's no way to really describe alot of what God is or is about short of analogy, thus our understanding is always incomplete. People, mostly, hate ambiguity though. Thus, lots of heat is generated by religious types claiming their analogy is the Truth.
At the same time, their is something about the human experience of God which leads to seeing God in distinct forms. The eternal God whose will underlies all of the Cosmos, existing outside of time and space, somehow remote and distant, Jesus of Nazareth who walked and talked and had to do all the things human do (yes, even those things) and yet in whose life and resurrection from the dead the earliest disciples experienced the divine, and all of the ways in which the divine purpose intersects our lives and makes its presence known to us; all three of these point to "God" and yet we cannot get over the feeling of separateness in them while somehow recognizing their unity of purpose and direction.
There is to mind, very little to say about the Trinity other than saying "in this mystery I believe and trust." But there is still much to be said about our experience of God, both in transcendence and in our relationships with others. I became a Christian not because of the beauty of it's arguments on behalf of God's existence or because of the internal logic of its theology (which it isn't). I became a Christian because of experiences I had whose explanation defied rational examination and the story of God as contained in the Christian tradition made the most sense, even if not perfectly.
To me, Christianity is an ongoing examination of the world around us and a testing of tradition and scripture in light of that experience. Faith is not about learning some arcane set of facts and holding fast to them in the face of contrary evidence. It is a journey of discovery and reconciliation of our experience of God with others' experiences so that all together we might discern and live into the one underlying truth of God; that our universe is founded upon the twin principles of love and relationship.