Tear Jerker / Adventures of the Gummi Bears

• "Light Makes Right" both begins and ends on these. During the flashback at the beginning, there's no dialogue (other than shouts of "Look!" and "Hurry!), just a vast crowd of bears running towards the coast as their homes burn behind them and gazing sadly at their destroyed home as they sail away. During the climax, Zummi tries his hardest to get the message sent from across the sea before the machine collapses, making you truly feel his pain when he fails. Yes, they saved the day, but they came so close to finally contacting the rest of their people, and to lose that opportunity somehow makes their situation seem more lonely than before they knew their friends were out there somewhere, alive and thriving but now completely unreachable. It's the ultimate Bittersweet Ending.
• "Up, Up, And Away": Most shows leave the Fridge Horror for the viewer to think of on their own. Not this episode! When Cubbi's the only Gummi left who wants to leave with Chummi to join the Great Gummis, Chummi tells them he understands because he was the youngest member of his clan, too... and now the last. Zummi then admits that they've actually "talked about this problem before" — that is, the fact that if nothing changes, their youngest member will eventually be left all alone one day! With that in mind, it's no wonder that Cubbi's family all apparently come to think it would be better for him if he left. Their good-bye scene is heartbreaking, reaching its peak when Gruffi gives him what would have been his next birthday gift, letting us see him cry real tears for the only time in the series. It's opening that gift later that makes Cubbi realize he can't bear to leave his family. Not exactly the type of atmosphere you expect to find in this colorful kids' cartoon about bouncing teddy bears...
• Really, the whole background of the series is pretty heartbreaking, "Up, Up and Away" is just one of the more prominent "in your face" portrayals of it. Gummi Glen used to be home to hundreds of Gummi Bears. But now, centuries later, the Gummis have dwindled away until all that's left is six of them. In the first episode, they've forgotten almost everything their ancestors knew about magic and technology, little better than ghosts just wandering the empty halls of their home and waiting to die. Even after Cavin brings them the last Gummi Medallion and lets them unlock the Great Book, they're still little more than remnant of what their people once were, and they know it. By the end of the series, the local population problem is solved with the Gummi Glenn Gummis merging with the larger Barbic gummi nation at the city of Ursalia.
• "Zummi Makes it Hot" has the Gummis, when their water abruptly stops, trekking through Drekmore to find the ancient Gummi pumping station that provides the Glen (and, Zummi opines later, likely every Gummi community in that part of the world) with running water (their water needs to be absolutely pure to make Gummi Berry juice, the pumped-in kind, Gruffi tells us at the episode's beginning, being the only kind that works). When they finally discover the pumping station and take in the size, sophistication, and complexity of it, Grammi, with what sounds like genuine heartbreak in her voice, says to Zummi "it's terrible what we've forgotten."
• The fate of the Tree Folk of Fangwood in "Day of the Beevilweevils" is truly tragic. After the Gummi inhabitants fled without warning, the sapient trees were abandoned without any ability to sustain themselves, or to leave the valley — and nobody even knew about their plight. After several centuries, a once-numerous species has dwindled down to just four last remnants, ironically mirroring the decline of the inhabitants of Gummi Glen.
• Gruffi is abolutely devastated to the point of burying his head in his hands and sobbing in "Gummi at Sea" when he believes Tummi has died attempting to sabotage the Gumarine he found after it gets stolen by Duke Igthorn. He'd been extra hard on Tummi and insisting he "grow up and act responsible" the whole episode, and really berates himself for being so hard on him.
• The fact that by the end of the show, after everything the Gummi Bears have gone through, they're still living in hiding.