Irony of Rank and Honor
People intuitively think that having a noble title or being from a noble family implies nobility in the sense of good character, but in this novel many of the aristocrats don't behave in an ethical or honorable way. Although there is social prestige attached to the "knightly" von Massenburg family, both Bertha and her father behave in a very greedy and venial way. Similarly, Albrecht von Osternau (who continues to use his military rank socially despite having been expelled from the cavalry for conduct unbecoming an officer) is a compulsive gambler who turns to theft and finally arson to pay his gambling debts.
Irony of Beauty
The most physically beautiful person in this novel is Bertha von Massenburg, who uses her looks to charm other people into advancing her interests. She willingly participates in her father's plan to marry her to Egon von Ernau, whom she has never met and knows only through his poor reputation. When Egon is reported dead, she instantly transfers her affections to the besotted Hugo von Wangen. Although at least some of the other characters disapprove of her blatant gold-digging, they excuse Bertha's conduct as something perhaps born of desperation. The extent of Bertha's ugly character does not surface until the second half of the novel, where she attempts to get rid of Hugo's younger sister Clara along with the impoverished and defenseless Elise. She sabotages the budding relationship between Egon and Elise solely out of spite. In a Romantic novel, good looks frequently accompany good character. Not so in Quicksands.
Irony of Egon's return
Egon initially leaves Berlin determined to kill himself in the woods near Breslau and is distracted only by the novelty of assuming Pigglewitch's identity and of passing himself off as an impoverished tutor. Having deliberately disappeared without warning, he makes no effort to inform his father or his friends of his whereabouts. At Osternau he witnesses the impact his departure has had on his fiancée Bertha, and begins to reconsider his prank especially once he meets Bertha in person. Over the next few weeks, Egon becomes increasingly attracted to Bertha, and he leaves Osternau only after news arrives that his body (which he infers was Pigglewitch's) has been discovered. Even then he does not hasten back to the capital, but spends a few days hiking in the mountains. Only when he runs into an old friend does he agree to return to Berlin. He does so, believing he can pick up his engagement to Bertha where he left off, but upon his "miraculous" return from the dead he finds that Bertha has moved on and is now engaged to Hugo von Wangen.
Irony of Egon's career choice
Egon shocks everybody with his intention to abandon Berlin in favor of the West Prussian estate he inherited from his mother. To most of the people in the novel the capital is far more exciting. That the pleasure-loving and mercurial Egon should prefer a quiet country existence is the opposite of what most of the other characters expect. Bertha, Albrecht, and the Baron von Ernau cannot comprehend why anyone in his right mind would prefer the country over the city. To anyone who knows Egon and his impulsive nature, his career decision appears to be just one more random whim he follows instinctively. The narrator, the reader, and Egon himself know that his decision is a hard-won conclusion and the first step in a departure from his empty and directionless life, but to the other characters it comes across as just one more wild impulse.
Irony of Deception
Bertha, in her attempt to avoid boredom, readily agrees to Hugo's proposal once it appears that Egon is dead. She claims to be highly interested in a rural life, however her eagerness to substitute one bridegroom for another ensures that she is no longer available when Egon returns to Berlin. Upon learning Bertha is engaged to someone else, Egon has the opportunity to arrange to have the engagement cancelled, but he chooses not to do so. Bertha's moral flexibility suddenly become obvious to Egon, and for the first time in his life he is able to resist temptation and the desires of the moment. Ironically, when he does this the people around him (specifically the Barons von Ernau and von Massenburg) interpret his decision to not interfere with the betrothal of Bertha and Hugo as another sudden change in direction on Egon's part.
