I think that one of the basic themes of the song is how parents expect their children to conform to their wishes.  The message in the song is how stifling parental pressure for children to achieve "the best" can be.  The song's lyrical chorus reflects this:

Be a good girl/ you gotta try a little harder/ That simply wasn't good enough/ To make us proud.

The theme here is that in their desire to see children succeed and "be the best," a toll is taken on a child.  Another way of seeing the theme here is that parents want the best out of their children because it masks their own failures.  Consider the lines "I'll live through you" or "I'll make you what I never was" as evidence of this.  The song stresses the theme that the driving for child excellence is motivated by a series of factors.  These contribute to an overall destruction of the child's psyche.  The end theme of the song is one in which children driven to be "perfect" end up paying the ultimate of prices for a pursuit that might not even be their own.