Two for One

In the opening of the book it is repeatedly said that Anna and Molly are interchangeable, or at least seem to be to their acquaintances. Their names are generic. Nothing too flowery or exotic. They have a similar past but different talents and social lives (though the common friends seem to muddle them into one another). This two in one, one in two thing is interesting to me. They could easily have been made into one character and most of their dialog condensed into interior monologues. One character with some conflicting ideas.  There is a bit of self-hatred, self-depreciation, and a want to save the other from that while continuing to commit the cycle of lack of  appreciation for themselves.