This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Cirque du Soleil
Episode 12 of Solstrom, entitled "Wind of Life" has the scene where the toy shop owner celebrates the birthday of his favourite toy. It may sound bizarre and a tad narmy, but it's an incredibly heartbreaking scene.
Amaluna has the Chinese pole scene, where Romeo and Miranda are separated and the Chinese pole climbing by Romeo represents his crossing into the Despair Event Horizon. The moving music doesn't help matters either.
Another moment in said show is when Romeo is sent back down to earth by the tight wire acrobats in purgatory, only to be trapped by Miranda's pet lizard.
After the "Battlefield" sequence in KA, the evil Counselor tries to comfort his equally wicked son, who has been blinded by his own explosives and is wailing in pain. The actors put so much emotion into it. It's telling that it's been dialed down since then, because it was probably Narm for other audience members.
The opening sequences of Quidam, "O", and Corteo have deeply moving music, and on top of that, in the last example it's for a gathering for the dead protagonist (the show is his deathdream as he ascends to Heaven).
The curtain call for Quidam: Most of the cast emerges as the Chienne Blanches — who are perpetually dressed in white, with face-concealing cowls, as befits the title's Latin meaning of faceless passerby. And then they remove them.
Another "O" moment is the "wedding" transition: A bevy of cheery brides and grooms cavort onstage until the music to the melancholy "Nostalgie" kicks in, the lights change, and a woman pushing a laundry cart takes the veils from each bride and tosses them in the cart as the dancers grow still. Combined with the business in the foreground between the Little Dancer and the two men who have fallen for her — Guifa and the slightly grotesque Eugen — climaxing when Guifa gives Eugen back the flower he hopes to woo her with, it's so sad, leading to a most welcome bit of Mood Whiplash when the mood revives for the Russian Swings act for the couples.
"Ninkou Latora", the song from Dralion that plays during the double trapeze. Towards the end of the song (4:03), the music gets so intense and powerful that it just suddenly floods you with emotion before calming down. Its even more tearjerking when set to the visuals on the DVD.
The ending of KOOZA is both heartwarming and gutwrenching, as both the Innocent and the audience have to accept that the adventure must come to a close.
The very end of Love is a clip of John Lennon laughing and saying "This is Johnny Lennon just sayin' good night to ya's all, and God bless ya's." There's just something about it...
"Birth of the Sky" from ZED, a beautiful ballad by Erato the Sky Goddess amidst a starry sky and flanked by four nymphs. It's followed by "Birth on Earth", its counterpart by Abraka the Father of Earth. Both songs come together to show a lot of love and passion the respective worlds have, and you know that their desire to come together will work out.