This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Batman & Robin
Mr. Freeze's reaction after Poison Ivy falsely informs him that Batman killed Freeze's wife is genuinely touching. He sheds a single tear, which freezes on his cheek.
And it becomes even worse for the Batman: The Animated Series fans who know that that scene was the planned ending of the episode "Heart of Ice".
At the end, Batman reveals to Freeze that he saved his wife, and has moved her to a secure facility where Freeze can continue his work for a cure. In the meantime, he tells Freeze that Alfred also has MacGregor's Disease and invokes a "I Know You Are in There Somewhere" Fight moment when he encourages Victor to remember the man his wife loved, and help him. Freeze thinks it over a moment, and then gives him the cure he needs to save Alfred.
The conversation between Bruce and the ill Alfred, in what might have been their last moment together, and thus, tell each other what the other has meant to them in their lives. Say what you like about the rest of this movie, but the prospect of Alfred dying is genuinely sad, especially as played by master thespian and professional Cool Old Guy Michael Gough.
Bruce: I still have you, Alfred.
Alfred: I shan't be here forever.
The brief scene of Mr. Freeze in his prison cell, carving a tiny sculpture of his wife and using a nearby clock and glass to turn it into a makeshift music box is rather touching amidst the sound and fury, and is a nice reference to the animated series.
Freeze watching home movies of his wedding.
After The Dynamic Duo suit up and have the usual banter with Alfred, as soon as they leave, the once composed Alfred starts looking as if he's in pain. This was the first sign that he was dying.
Robin being manipulated by Poison Ivy for most of the film. He really thinks she loves him and is ready to leave Batman to be with her, and she is really just trying to kill him with her poisoned kiss. Robin might have trusted Batman in the end, but maybe there may have been a part of him that was sad to find out Poison Ivy had been lying about loving him, and hoped that a kiss with her would prove their love was real. It is also subtlety implied by Robin telling Ivy that he "wants them to be together," that had Ivy’s love been real, he was going to ask her to marry him, maybe even tell each other who they really are so they can be more than just Robin and Poison Ivy, but Dick and Pamela too. Instead, immediately after their kiss, Ivy taunts him by saying their kiss was for "bad" luck, revealing her true colors and mocks him by continuing to flirt in a mock sad tone. There was more of this in an unused part of the script, where she tells Robin she never loved him at all.
Ivy: (grabs Robin as he leaves and speaks sweetly) One kiss, my love...(whisper)For luck. (Robin leans in, unaware Ivy has an evil smirk on her face, and they share a romantic, passionate kiss) Ivy: (mock sadness as she rubs noses with Robin and strokes his chin) Bad luck I'm afraid. Time to die, little Robin. (Ivy leans back smirking to watch her newest victim die)
Then after Robin reveals he managed to survive her kiss by wearing rubber lips, Ivy angrily leaps forward and shoves him off the romantic rose throne they had been sharing, the place they had just been flirting on and shared their first kiss, and he splashes into her pond where her plants immediately turn on him and try to drown him. As Robin struggles for air, Ivy just walks off with a smirk, mockingly waves him goodbye and taunts him by shouting "See ya!" in a condescending voice. In short, she was "breaking up with him." Not only was Robin tricked and manipulated by Ivy for most of the film, he finds out her love was a lie and she dumps him by trying to drown him immediately after finally sharing a kiss with her.