The story revolves around teenage Joan whom God begins appearing to in various human forms. He gives her simple assignments which she at first eschews. It's a little hard to wrap her mind around God appearing as a trash truck driver or a hot guy at school. God just shrugs. She has a free will, and he can't make her do the things he asks. Of course, she's a good kid and does eventually obey. For the most part.
But this isn't a commercial for Joan of Arcadia. What struck me after watching one episode in particular (I believe it was "The Fire and the Wood"), was something God said to Joan. She didn't understand how her getting a job at the local bookstore or joining the AP Chem class had anything at all do do with, well, anything. What difference did it make?
God then explained reality strands. Joan did something that affected somebody who then did something that affected Joan who then did something to help somebody else, and on and on and on. What God was saying to Joan was you do what God asks because He asks, not because you can see how it'll all pan out. Later, you might see it, but even if you don't, God does. He knows how something that seems inconsequential to us can vastly affect a life.
I thought that was a really cool explanation. It reminded me how I need to listen to the still small voice of God (since that's how he most often speaks to us) and obey it ... even when I can't see what difference it could make.