Christians all supposedly worship the same God, who goes by various names- Yahweh, the Lord Almighty, Our Father, etc. However, despite the emphasis given to monotheism in Christianity, what Christian theology yields is a new sort of polytheism, not appreciably different from paganism's assortment of gods and spirits. This derives from the multi-faceted way that the God of the Bible is depicted and characterized in the scriptures. God is said to be loving, angry, jealous, protective, threatening, constant, vacillating, patient, frustrated, rigid, mysterious, and caring. This list runs the gamut of human attributes, and out of this array of characteristics it is perfectly easy to construct a God of your own choosing to worship and follow or emulate.
No matter what attitude, emotion, or worldview you might want to embrace, there will be an accompanying aspect of God from which you can draw support. If you want to be angry with certain people and do them harm, there is a God for you. If you want to separate from most of the world and hide out in a special enclave of the like minded, your God is in the Bible. If you want to engage the world and see it as one unified humanity despite its obvious differences, that God is also available to you. If you want to promote peace and reject negative emotions, the Bible yields a supporting deity. God of war, God of peace, God of love, God of judgment- they are all there in the pantheon of Christian theology.
All these various ways to draw a personal God from the Bible are on evident display throughout Christendom. In fact, this very polytheism largely explains all the internal conflict that has roiled Christianity throughout its history. When the one God can be so dramatically different from one moment to the next, one passage to the next, confusion and differences between Christian groups are inevitable.
If one adheres to the traditional understanding of the Bible as God breathed, meaning that God chose each and every word in the book, it will remain impossible to have a realistic Christian monotheism. A God of multiple personalities is effectively no different from multiple gods, and a religion based on that God cannot truly differentiate itself from those of the ancients.