This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Pokémon Black and White
N's Farewell theme. It even has some parts that sound like the MOTHER 3 Love Theme and A Letter From You, My Sweet from the same game. The entire scene it plays over- when he bids one last farewell to the player and thanks them for helping him find the truth- is pretty touching as well for a Pokémon game.
Not to mention being one of the most heartbreaking Anti Villains in fiction, with his farewell theme practically driving his Anti-Villain status home.
It could actually be happy, because he's off to finally see the world for himself and find his own purpose in life.
Likewise, N's playroom gives a rather disturbing and heartbreaking vibe. It has an eerie, childish remix of his theme playing in the background. Whether it's more disturbing or heartbreaking is probably up to the player, but there's something very sad about reading the text about all the toys which were just recently played with, even though N is an adult. It really drives home how isolated he's been his whole life. When you combine this with the psychological Fridge Horror of Ghetsis' emotional manipulation, it makes you pity N more than any other character in the whole franchise.
A sort of meta example, but Nintendo has said on record that Black and White were a "re-visioning" of the series. They wanted to capture the original feel of the very first games, as if you were starting all over again. And then you get songs like these where the wave of nostalgia just threatens to let the waterworks loose.
The first time that music plays, when Bianca's father appears at Nimbasa City to try and take her home... For Bianca fans, it's an especially depressing moment.
The girl asking you to ride the ferris wheel with her in Autumn, feeling depressed knowing that summer is over and all her friends are at school or on journeys. Once actually riding the wheel with her, she begins to stutter with sadness and asks to sit next to you until the wheel descends.
Likewise, there is a kindergartener in Winter who asks you to ride with her, and then after the ride talks about how her father just comes home late after work and sleeps, never spending time with her. A player can infer that her father was an alcoholic, just coming home after drinking all night and passing out. Hell, you don't even need the alcoholism angle to make this sad. This could simply be a girl with a dad that she loves dearly, but he's so focused on his job that he doesn't have the time or energy to give her once he's done. He's addicted to his job and chasing success - even if he might have started out with good intentions in the beginning. Given that Word of God states that culture in Unova is based roughly on American culture, the implications that are there are equally painful.
Or you could read it as her parent(s) being in a poor financial situation and her dad needing to take all the hours he can get to provide for her family. Really, the ideas are endless.
One of the people you ride the ferris wheel with is a sickly young man. It takes all of his willpower to get to the ride and back home.
What makes it sadder is that the rest of his Trainer class, the Rich Boy, tend to be rather stuck-up and arrogant, but Martin is sweet and sincere. His dialogue makes it sound as if he's dying and all he wanted was a Pokemon battle to give him and his Tranquill some exercise and go on a Ferris wheel with a friend (or even as a date), before he died.
"Each of them carries a mask that used to be its face when it was human. Sometimes they look at it and cry."
It gets worse. In the free 3DS app "Pokédex 3D", if you manage to get Yamask downloaded from the internet, chances increase if you scanned its AR marker earlier, you can press A to initiate its animation. It takes the mask it holds, lifts it up, and looks at it. It appears to be in joy, but you can tell that it's apparently faking happiness.
How about Alder and his dead Pokemon? Throughout the game you only hear bits about it, but after the Elite Four is beaten, you get pretty much the whole story of Alder and his Pokemon when you meet him atop Celestial Tower, and that's where it reaches full Tear Jerker status. Why's Alder there, you ask? That's where his Pokemon was buried. And he rings the bell there...to comfort its spirit.
Another example from the Celestial Tower: One of the random trainers you can battle says she has a really strong Pokemon. Upon beating her, she remembers that she doesn't have one, at least not anymore. Considering that this is the Celestial Tower, it's not too hard to connect the dots.
Everything about N. From his past, to the soul-crushing way in which his father betrays him by calling him a freak without a human heart (N isstruck silent for that entire scene), this character WILL make you cry by the the end.
And, in a kind of meta example, the official title for N's leitmotif is 'Prisoner to a Formula'.
YMMV, but the scene in Nimbasa City with Bianca and her father where he finally accepts her journey is both this and heartwarming, especially if you're about to make a big step in life yourself.