The irony of America's relationships
America realizes that she in fact does have feelings for Maxon, and is therefore jealous when she sees that he spends time with other girls. On the other side, she goes off to spend time with Aspen, while she knows Maxon has feelings for her.
The irony of Marlee's punishment
When Marlee is caught for having a relationship with another man than the prince, she is punished with caning and removal of castes, while Maxon is encouraged and forced to spend time with numerous girls at once.
The irony of the presentation
The Selected girls are told to speak about something they hold dear and deem important on live television, but when America does, she gets shut off, because it is to "radical" and "important".
The irony of the ball
Maxon tries making America happy, and orders there to be a Halloween party. The night of the ball, however, Marlee is caught having an affair, which ruins America's days.
The irony of Maxon's punishment
America holds lots of grudges against Maxon because of the events that take place. However, she doesn't know about the punishments he has received from the king because of her.