This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Winnie-the-Pooh
The ending of The House at Pooh Corner: Christopher Robin is going away. It's implied he's going to boarding school, which means he won't see his friends again. The characters don't know the specifics, but they band together and write him a goodbye note. As they host a farewell party, Eeyore realizes that the boy wants to be alone with Pooh, and tells the others to leave. Christopher Robin then takes Pooh to 'An Enchanted Place at the Top of the Forest'. They talk together about doing nothing. Christoper Robin mentions that 'they don't let you do nothing. Not for long, anyway.' He tells Pooh of things he'll learn at school—about countries, Kings and Factors, eventually making him his best, most faithful Knight. Then the ending.
"Pooh, promise you won't forget about me, ever. Not even when I'm a hundred." Pooh thought for a little. "How old shall I be then?" "Ninety-nine." Pooh nodded. "I promise," he said.
Still with his eyes on the world, Christopher Robin put out a hand and felt for Pooh's Paw. "Pooh," said Christopher Robin earnestly, "if I — if I'm not quite —" he stopped and tried again — "Pooh, whatever happens, you will understand, won't you?"
"Understand what?" "Oh, nothing." He laughed and jumped to his feet. "Come on!" "Where?" said Pooh. "Anywhere," said Christopher Robin.
So they went off together. But wherever they go, and whatever happens to them on the way, in that enchanted place on the top of the Forest a little boy and his Bear will always be playing.
Surprisingly, the ending was copied almost word for word in the ends of both The Many Adventures of Winnie The Pooh and Pooh's Grand Adventure. Slightly toned down yes, but the implications are still the same-and it's just as sad.
Rabbit's Bad Future if he succeeds in making the first say of Spring officially "Spring Cleaning Day". His friends will find him so overbearing and controlling, that they will all move away and leave him alone.
The backstory explaining why he's come to hate Easter. After one especially overbearing year as the Easter Bunny, Tigger snuck off with the eggs and the gang went to do hunt them without him. This wasn't what broke Rabbit however. It was how much Roo loved Tigger playing Easter Bunny. He felt rejected since he wanted to make something nice for Roo, but couldn't compete with his Big Brother Worship of Tigger.
Winnie the Pooh (2011)
The trailers, with "Somewhere Only We Know" playing over them. Really hits home for people who have grown up with these stories and are adults now.