To keep within Christian ideology: we are here in this world, with the "knowledge" of good and evil. You cannot have a concept of good without being able to identify it against the concept of evil. I often wonder that outside of this realm, the aspects of "good and evil" are not so important and ominous.

Here there is this duality, and we must "choose" a side it seems. As you indicate, every action - big AND small - is a choice to do "good" or "evil, and being a "good" or "evil" person is not as obvious as they make it seem in the movies.