The last fight before the final round, Tommy crying to himself against the cage realizing he isn't going to win with a broken shoulder.
The entire scene of Paddy meeting Tommy in the casino. He attempts to commemorate his rescue of a marine in the war, only to find out that at the time, Tommy had been illegally fleeing his troop. Paddy tries to be understanding and supportive, but Tommy's having none of it and proceeds to give him a humiliating verbal beatdown and drives him away. Cut to the next morning when Tommy returns to the hotel to find his father a wreck once more, drunk again after one thousand days of sobriety, wandering around his hotel room as though lost and sobbing deliriously. This scene is painful enough through the sheer hurt and misery on Paddy's face, but even moreso for Tommy's response when faced with the scene: a quiet My God, What Have I Done? moment, followed by Tommy cradling his drunk father on the bed, petting his head and shushing him to sleep.
This troper found all three of the main characters remarkably sad and tragic. All three of them weren't necessarily in the right with their wants, regrets, anger, etc. but they also weren't wrong either. Paddy is genuinely making strides to stay sober and reconnect with his family and is so different that even Tommy acknowledges it but also tells him it's too late and he doesn't need the person that he is now. The constant playing of "Moby Dick" could also very well be a form of therapy recommended by a psychiatrist as a means to live with his wartime experience. Tommy's anger and rage is absolutely understandable especially his feelings towards his family: His father was an abusive drunk and it's implied he put a whole lot of attention and pressure on Tommy, especially in athletics. His anger toward Brendon is also completely understandable as Tommy was all of 13 years old when they made plans to leave and Brendan abandoned those plans and Tommy had to take care of his mother while she was sick and dying by himself. Finally, his best friend was killed in a friendly fire incident. It's no wonder he's so pissed off at everybody! Finally there's Brendan who didn't seem to get much attention from his father, and got completely cut off from his mother and brother to the point where he apparently found out his mother passed away long after the fact. It's almost like a twisted sort of love triangle (a platonic one) with all three of them.