How does Wilde use the country vs city life as examples to show satire against the upper class?
Wilde specifically takes digs at country life versus city life in the showdown between Gwendolyn and Cecily on Act 2, Part II.
As Gwendolyn comes from the "fashionable" city of London to visit her Earnest in his country manor, she feels threatened by Cecily's presence there, and thinks her to be quite plain and silly.
Since both women were confused as to which of them was actually marrying Earnest, they began a sarcastic showdown that went like this:
Gwendolen. Are there many interesting walks in the vicinity, Miss Cardew?
Cecily. Oh! yes! a great many. From the top of one of the hills quite close one can see five counties.
Gwendolen. Five counties! I don’t think I should like that; I hate crowds.
Cecily. [Sweetly.] I suppose that is why you live in town? [Gwendolen bites her lip, and beats her foot nervously with her parasol.]
Gwendolen. [Looking round.] Quite a well-kept garden this is, Miss Cardew.
Cecily. So glad you like it, Miss Fairfax.
Gwendolen. I had no idea there were any flowers in the country.
Cecily. Oh, flowers are as common here, Miss Fairfax, as people are in London.
Gwendolen. Personally I cannot understand how anybody manages to exist in the country, if anybody who is anybody does. The country always bores me to death.
Cecily. Ah! This is what the newspapers call agricultural depression, is it not? I believe the aristocracy are suffering very much from it just at present. It is almost an epidemic amongst them, I have been told. May I offer you some tea, Miss Fairfax?
This was the way Wilde showed how the city people viewed the country folk and vice-versa. In the dialogue the two women had tea, and even the food was a problem that led to another showdown that went like this:
Cecily. [Sweetly.] Sugar?
Gwendolen. [Superciliously.] No, thank you. Sugar is not fashionable any more. [Cecily looks angrily at her, takes up the tongs and puts four lumps of sugar into the cup.]
Cecily. [Severely.] Cake or bread and butter?
Gwendolen. [In a bored manner.] Bread and butter, please. Cake is rarely seen at the best houses nowadays.
Cecily. [Cuts a very large slice of cake, and puts it on the tray.] Hand that to Miss Fairfax.
[Merriman does so, and goes out with footman. Gwendolen drinks the tea and makes a grimace. Puts down cup at once, reaches out her hand to the bread and butter, looks at it, and finds it is cake. Rises in indignation.]
Gwendolen. You have filled my tea with lumps of sugar, and though I asked most distinctly for bread and butter, you have given me cake. I am known for the gentleness of my disposition, and the extraordinary sweetness of my nature, but I warn you, Miss Cardew, you may go too far.
In general, the fashionable Londoners always looked down on the country people who chose to live there instead of just having a home in the city and one in the country. It was understood that such persons chose not to live in London because they were not sophisticated nor wordily enough to keep up with the aristocrats, et al. You can see the same form of classicism in Jane Austen's Pride and Prejudice, in Dickens's Great Expectations, and in Sense and Sensibility as well.