Proposal (Situational Irony)
After talking about asking Doogan for Kate's hand in marriage, Gar is unable to muster the courage to do so, and this costs him a relationship with his beloved. Even when Doogan all but offers Gar Kate's hand in marriage by saying that the most important thing to him is Kate's happiness, Gar feels too demoralized by his feelings of inadequacy and inferiority due to his class. This moment is ironic, because we know that Gar is in love with Kate and could fight through his feelings of insecurity in order to be with the woman he loves, but he does not do this. He leaves abruptly, giving up his relationship with Kate forever.
Madge invited the boys over (Situational Irony)
At the end of his time with his friends Ned, Joe, and Tom, Gar is disappointed with the fact that they were not especially expressive about his leaving, but he is also grateful to them for coming over. However, as he is leaving, Joe reveals to Gar that the only reason the boys came over in the first place was because Madge invited them. This ironic twist leads Gar to feel even more disappointed in his friends.
S.B. and Gar missing each other (Dramatic Irony)
After spending much of the play trying to muster the courage to speak to his father about a shared memory, Gar finally does so in the early morning before he leaves. Because we have been privy to Gar's inner thoughts, we know that sharing this memory is particularly important to Gar. S.B., however, does not know how important this memory is to Gar and disappoints his son when he does not share the same memory. This moment constitutes an instance of dramatic irony, in which the audience knows the extent of Gar's investment, while S.B. does not.
Then, when Gar leaves the room, frustrated, S.B. confides to Madge that he has such happy memories of Gar wanting to leave school to come work in his shop. While he is unable to share these fond feelings with Gar, the audience is privy to S.B.'s affection for his son. This is yet another moment of dramatic irony, in which the audience knows more about S.B. and Gar's feelings towards one another than they do.
Private Gar (Dramatic Irony)
A recurring dramatic irony throughout the play is the fact that the audience can see a "Private Gar"—a side of his identity that no one else can see. As a result, we are privy to his private thoughts and feelings in a way that other characters are not. His thoughts are evident to the theatrical audience, but the identity he shows the public-facing world is quite different.
