"I suppose... there will be no one to call me Matilda now." Damn it, Judi Dench!
Walter's death. When a small child dies, it always feels terribly sad, but his father and sisters' distress is excruciating, especially Sophy's who is in the position of the mother and blames herself for not being careful.
Mr Carter's death and the way poor Harry mourns him, thinking he lost his only friend and guardian. How he reads the poem and gives him the book in the coffin...
Most mentions of Miss Matty and Mr Halbrook's relationship are extremely sad. But particularly the moment when they rekindled the romance and were about to be together, Mr Holbrook's death makes an end to it. Miss Matty mourns him deeply, and would like to wear widow's bonnet, but she cannot.
Laurentia Galindo weeping over Harry's body toward the end of Return to Cranford is absolutely heartbreaking. When Emma Fielding wants you to cry, you cry hard.