Pretty much any scene in which Elton interacts with his father. The man is a dog-kickingmachine.
In particular the scene late in the movie where Elton tries to have a reunion with his father who now has a new family and two other sons, with whom he is way more affectionate than he was ever of Elton. He even stops Elton from writing 'For Dad' when asking to sign a record, claiming it's for a colleague instead. Elton can hardly hold in tears as he struggles to say his farewell to his father, before breaking down completely inside the cab after he's out of his father's sight. It's so bad that the present Elton, who's recounting his story to the group therapy session, frustratingly gets up and slams his chair to the floor in anger, showing that this event still has an effect on him up until this day.
To make matters worse, he even asks the group on where the alcohols are located, indicating that he wants to wipe away the anguish by any means necessary despite the fact that he attended the Rehab in order to become sober.
Elton: What've you got to do to get a fucking drink around here, eh?
Right after the above, the scene where Elton comes out to his mother is utterly heartbreaking. It's funny at first, with her bluntly saying, "I know," but then she says that she wants him to "keep it to [himself]," and that he's choosing a life where he can't ever be loved properly. The poor man looks utterly crushed as he hangs up, and he starts to tell John what happened... and John's response is to yell at him for being late to a show. It gets even worse when Elton shoves him in anger and John deciding to slap him in the face, proving this point further.
Elton: She said I'll never be loved.
(John angrily grabs him)
John: Don’t ever put me in this position again. You’re on stage in 10 minutes so get over yourself and do the show. We’re running a business here, you fucking idiot.
(Elton shoves him)
(John violently slaps him in the face)
John: Don't ever put your hands on me.
(John storms off)
If you think about it, the way the scene plays out is defeating; his mother tells him that he'll never be loved properly, then the person who Elton thinks loves him, hits him in his time of need, proving that he doesn't care about him.
"FOR MY NEXT TRICK!... I'm gonna fucking kill myself."
John's frequent dismissal of Elton's struggles are this: he hits Elton when he tries to talk to him about his mother's rejection of his sexuality, when Elton is being carried into the ambulance during the "Rocket Man" sequence you can see that Reid is angry at him for nearly dying, Reid insists that Elton is fine and should be performing more after Elton has a heart attack (Hell, even his employer is concerned about his health when he calls John Reid before the Madison Square concert and even calls him insane after Reid tries to book five more nights, pointing out that he could have died!).
Sheila telling Elton she's ashamed to be his mother. Just after asking him for money to buy a mansion abroad.
"Goodbye Yellow Brick Road," just the whole thing. It starts with Bernie deciding to cut ties with Elton (briefly) believing himself to be expendable "there's plenty like me to be found" and unfit to live a life like Elton's. And then Elton himself tries to prepare for a show at Madison Square Garden but can only look in the mirror with a disappointed expression and wrestles with the choice to stay or leave. He sounds like he's on the verge of tears as he sings, but he eventually grows more confident the further away from the show he gets and ultimately checks himself into rehab. Beginning his road to redemption.
Then there's Elton's reaction to Bernie leaving during the above mentioned scene. As Bernie walks away, Elton starts off snarking about getting the bill and then he yells Bernie's name loudly. And when that doesn't work, Elton starts to get more desperate as he runs after Bernie to try and stop him from leaving. And as Bernie leaves in a cab, Elton then resorts to insults ("COWARD! SAME AS ALWAYS! LEAVING ME WHEN THINGS GET TOO REAL!"). After that, Elton goes back to his townhouse, sits down on the stairs, and mumbles, "You idiot," before shouting, "YOU FUCKING IDIOT!"
The scene towards the end where Elton (in group therapy) sees his parents, his grandmother, John, Bernie... and his child self.
The ending is a tearjerker of the happy variety, as the "Where Are They Now?" Epilogue reveals Elton has been sober for over twenty years, is now Happily Married with sons, is still friends and collaborators with Bernie, and loves his life. You just want to cheer, but you're too busy sobbing.
Elton's marriage with Renate Blauel doesn't last long, due to his homosexuality. The former admits to the rehab group that Renate didn't deserve to be put in that position and that she deserved better
What makes it more sad is realizing how desperate Elton was to feel loved by anyone at this point in his life, even if it means going against his own sexuality
During the wedding, Bernie, John, Sheila are aware that the marriage won't last and it shows through their expressions
