Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.

The entire series is this given Miko's near-constant state of fear and misery. As for specific examples.

General

The anime's opening, Mienaikara ne!?, while cute and funny is actually mortifying once you realized that the lyrics are basically describing Miko's entire situation. We even hear Miko desperately pleading to the ghosts to stop following her.

Episode 2 and Chapter 4

The scarred man's life is pretty sad as the epilogue of the episode reveals that he lost his wife and two previous cats. But it also instills tears of joy due to the serene look his wife gives him indicating that she is pleased that her husband had someone to care for now.

Episode 4 and Chapter 9

At first, it seems like your typical chapter where Miko has to ignore a giant troll-like creature while having breakfast with her family. Until The Reveal that Miko's father has been dead the whole time and what she was actually avoiding was confronting her father for the first time since his passing. There's even some implied Parting-Words Regret where Miko and her father had an argument over some chestnut pudding, which Miko had bought earlier in the chapter to give to her father's shrine.
Miko: I'm not sure how I feel about seeing my Dad's ghost.

Episode 5 and Chapter 13

Miko helps a senile woman return home. The fact that this is a situation where an elderly woman had forgotten a lot of things in her life up to and including her own daughter's name is depressing. But it too ends on a happier note: the combination numbers her husband repeated allow her to open a safe to retrieve a gift her husband left her and she gets her memories back.

Episode 8 and Chapter 16

Turns out Miko and Hana's teacher tried to have a child once, but she lost it during childbirth. Miko then realizes that the spirit swirling around her teacher was her deceased son who reaches out to touch his mother's finger to grant her his blessing.

Episode 11

Zen's backstory is truly upsetting: far from being the cat killer as assumed, he was emotionally and psychologically abused by his overbearing mother who flipped out once when he made a 98 on a test and emotionally blackmails him into having no friends, so as to keep him all to herself. Worse, when Zen discovers a black cat and decides to take care of it, his mother kills it out of anger. The ghostly cats that follow Zen do so out of sympathy.