Sam's Crush (Situational Irony)
Early on in the film, Daniel is worried about his stepson Sam, who has taken to shutting himself in his room for long periods of time. He worries that something serious is going on with the boy, and his worries are made worse by the fact that he is unsure of how to connect with the boy. When he finally gets Sam to tell him what is going on, however, he learns that Sam's problem is that he has a crush on a girl at school. He is relieved to find that Sam's problem is something that he can actually help him with, and the moment of revelation comes as a great relief.
Jamie and Aurelia communicating (Dramatic Irony)
A charming instance of dramatic irony occurs whenever Jamie and his housekeeper, Aurelia, try to communicate. She only speaks Portuguese and he only speaks English, which makes it so that they can never understand each other. The viewer, however, can see subtitles for Aurelia's dialogue, which creates dramatic irony, in which we know something the characters do not.
Mark loves Juliet (Situational Irony)
Mark behaves very coldly towards Juliet, his best friend Peter's wife, throughout much of the film. Peter cannot understand why his best friend isn't more welcoming to the love of his life, and when Sarah encounters Mark at the wedding, she asks him if he's in love with Peter. Thus, it is ironic when Mark reveals that his cool attitude actually has to do with his love for Juliet. When she comes over and looks at his tapes from the wedding, she sees that every shot is a close-up of her, which confirms that Mark's unfriendly attitude had to do with his fear of being found out.
Harry's Affair (Dramatic Irony)
Every scene between Harry and Mia flirting represents an instance of dramatic irony. Harry is flirtatious with Mia and does not talk about his wife, Karen. Thus a gap opens up between what we the viewer know and what Karen knows. This dramatic irony comes to a climax when Harry buys the necklace at the store, while Karen is looking for something else.
