In an example of situational irony, Mr. Tulliver spends hundreds of pounds on Tom’s education—believing that it will help him to become financially successful—only to find that it has not prepared Tom for the workforce at all. Mr. Tulliver communicates his intentions early in the novel:
“What I want, you know,” said Mr Tulliver — “what I want is to give Tom a good eddication; an eddication as’ll be a bread to him. That was what I was thinking of when I gave notice for him to leave the ’cademy at Ladyday. I mean to put him to a downright good school at Midsummer. The two years at the ’cademy ’ud ha’ done well enough, if I’d meant to make a miller and farmer of him, for he’s had a fine sight more schoolin’ nor I ever got: all the learnin’ my father ever paid for was a bit o’ birch at one end and the alphabet at th’ other.”
The quote shows (in Midlands dialect) Mr. Tulliver’s logic—he wants to help Tom become “more than a miller and farmer” by sending him to school. (It is notable that Tom does become a successful businessman, but not because of what he learned during his studies.) This is an example of Mr. Tulliver’s provincial ignorance—he sends his son to the type of "gentlemanly" schooling that is focused on Latin, philosophy, and the arts, not understanding how it is different from a trade school or practical education.
A second layer of irony in regards to Tom’s education is that Maggie would have excelled at school the way that Tom couldn’t, as this type of education would have actually matched her interests and ambitions. Yet, because she is a woman, she is not allowed to access this kind of higher learning.
Stephen falling in love with Maggie when he is pursuing marriage with Lucy is an example of situational irony. Stephen’s feelings for Maggie are ironic because Lucy, according to everyone in St. Ogg’s, is the epitome of feminine beauty (she is even referred to as the “Belle of St. Ogg’s”), with her blonde curly hair and caring, gentle demeanor.
Maggie, on the other hand, has long, dark hair and prefers to read or go on adventures to the river rather than learn to sew or perform domestic tasks. She thoroughly challenges the social expectations of women in their society and, according to her parents and various aunts and uncles, will never find a husband because of it.
The following passage captures Stephen’s awareness of the irony of his desire to be with Maggie instead of Lucy:
It was all madness: he was in love, thoroughly attached to Lucy, and engaged — engaged as strongly as an honourable man need be. He wished he had never seen this Maggie Tulliver, to be thrown into a fever by her in this way: she would make a sweet, strange, troublesome, adorable wife to some man or other, but he would never have chosen her himself. Did she feel as he did? He hoped she did — not.
The quote demonstrates how Stephen is aware of the irony, as he calls the situation “madness” and even acknowledges that Maggie is “strange” and “troublesome,” while desiring her anyway.
After Maggie returns from running away with Stephen, the townspeople of St. Ogg’s judge her fiercely and essentially ostracize her, assuming her to have had an extramarital affair with him. The narrator points out the situational irony inherent in the townspeople’s judgements in the following passage:
We judge others according to results; how else? — not knowing the processes by which results are arrived at. If Miss Tulliver, after a few months of well-chosen travel, had returned as Mrs Stephen Guest — with a post-marital trousseau, and all the advantages possessed even by the most unwelcome wife of an only son, public opinion, which at St Ogg’s, as elsewhere, always knew what to think, would have judged in strict consistency with those results.
As the narrator notes, people are judging Maggie based on the results of her actions rather than the actions themselves—if they were really judging her for the act of running off with Stephen, then whether or not she returns married should not change their opinions (and yet it has).
This passage highlights the hypocrisy and lack of tolerance of 19th century British society as it relates to women—even though Maggie did not have a sexual relationship with Stephen, the mere fact that she spent time alone with him is enough for her to be cast aside.