It is well known that many actors relish taking on challenging roles. It helps them grow as actors and, perhaps on a personal level, presents unique opportunities to plunge deeper into the human psyche, both theirs and others. So, they research the role, often talk to those whom they will portray, and try to create that role in their mind.  Then in the scenes, they shift gears from their normal selves to that role even if that role is diametrically opposite to their normal self.  They compartmentalize the role within themselves and act within that compartment, but they still have a unitary self. Then when the scene is over, they shift back to their normal selves but they may also experience some change because of the experience of “the other self” in the role. This could represent God-as-transcendent, being changed by God-as-living in each aspect of the Divine Life. What this analogy suggests is that God seeks out the challenge of living perhaps because it evokes the most admirable qualities — courage, resolve, grace in the face of adversity, altruistic love, concern for both self and others, progressive action, growth etc. In other words, God taking on distinct lives is because God saw something so wonderful and valuable about living within constraints.