One of the funniest things about Wilde's play is the theme it conveys, that manners seem to be so much more important to the upper class than morality. Characters routinely do that which is proper rather than that which is good. Algernon has a very proper excuse for missing his aunt's dinner party: he is visiting his ailing, invalid friend named Bunbury. It is all quite appropriate and mannerly. However Bunbury is not actually a real person, he is a fiction invented by Algernon so that he has an acceptable reason to escape dreary, obligatory social functions. Bunbury, in other words, is a lie. Algernon nods to propriety and etiquette by inventing a socially-acceptable reason to miss the event, but he has no concern for a code of ethics that would prohibit him from lying.

Jack does the same thing with his invention of a dissipated brother named Ernest. He can come and "be" Ernest in the city where he does not have to uphold the high moral tone he feels is required in the country. Meanwhile, he seems quite mannerly when he tells his household that he must go and care for his troublesome brother. It looks like he's doing something great when, really, it's just the opposite.

In The Importance of Being Earnest, by Oscar Wilde, the themes of manners and morality are treated trivially (in Wilde's own words) because they are interconnected for very shallow and superficial reasons. That is what gives it the ironic nature that makes the play a comedy of manners.

Morality is a consistent topic in Wildean literature. Part of it is because Wilde's own morality (which was a thick topic in Victorian England) was often questioned, especially after the publication of his only novel, The Picture of Dorian Gray. He was so attacked that he basically counterattacked by characterizing morality as a superfluous behavior that goes hand in hand with manners. In other words, he would treat the topic of morality, which is a deep symbol of character, as a learned behavior that could be disrupted at anytime, just the same as manners. Hence, if you act like you are highly moral you can be deemed as a person of good manners. This is meant to be ironic, sarcastic, and humorous.

In The Importance of Being Earnest, morality is a game of manners. Lady Bracknell, for example, had the exaggerated mannerisms that were typical of snobby aristocrats. She turned her nose at Algernon's friend, Jack, because she did not consider that he or Algernon were "well-behaved”. However, that immediately left her mind when Jack mentioned his substantial income and his many properties.

Algernon also had the most polite and cultivated mannerisms in the play, but he led a life that left very little to say for morality: He lied to his family, escaped responsibilities, ran bills that he did not pay, plus he ate and spent excessively. However, Algernon would place more importance in his dress suit than in his moral life.

Jack was quite polite to Lady Bracknell, showing the most gentlemanly mannerisms that he could show in order to earn her blessing to marry her daughter Gwendolen. However, after receiving the ill treatment that he got from her for not having a "family name", he called her a "gorgon" and many other insults. Algernon was not upset. In fact, he said that "he loved to have his relatives abused".

Therefore, we can conclude that mannerisms were shallow masks of politeness just like morality was a shallow mask of character. They were both behaviors that were not necessarily inherent to the characters, and could disappear at any given moment.