You let her alone, mother. Let her speak for herself. You will jolly soon see whether she has an idea that I haven't put into her head or a word that I haven't put into her mouth. I tell you I have created this thing out of the squashed cabbage leaves of Covent Garden; and now she pretends to play the fine lady with me.
I think a political lesson that Pygmalion teaches is that one's social mannerisms and habits (i.e. setting the table correctly, saying polite things, etc.) are completely contrived from the people around you and don't change one's heart or personality. Higgins says "I have created this thing out of the squashed cabbage leaves of Covent Garden; and now she pretends to play the fine lady with me", showing how Liza's transformation into a lady was nothing of substance. Her heart or mind did not change, just her quirks and mannerisms. Liza later goes onto say that a lady is defined by how she is treated, not by how she behaves. Liza is saying that a lady is someone who is respected by society, not someone who can behave and act properly. The catch about this respect, though, is that one has to behave properly in order to get respect. Pygmalion is showing the error and fallacy of this dilemma by giving the character Liza, showing how her "transformation" gained her respect, even though she changed nothing of substance. The play demonstrates that classes are defined with nothing of substance, and suggests that one look at the character and heart of a person, not at how they behave at the dinner table.