Familial insults are one of the oldest forms of antagonism, in both real life and fiction, used to varying degrees of effectiveness; insulting someone's family member(s) can be portrayed as anything from minor pettiness, all the way to outright hostility.
Another variation involves mistreating the recipient because of whom they are related to, whether because of what their relative did, or because of who their relative is.
A third variation involves making fun of someone for coming from an impoverished or affluent family background, as if they have a choice in the matter.
See also Bastard Angst and Affair? Blame the Bastard, which, because both tropes (especially the latter) often involve mistreating the recipient for being born out of wedlock, or due to an affair, would involve insulting the parent of the child born of wedlock. Compare Sins of Our Fathers, when the hostility towards a family goes beyond petty insults. Also see Relative Button for examples where the family being insulted is dead.
No Real Life Examples, Please! There is enough incivility on the internet alone that cataloguing it in real life becomes gratuitous.
- JoJo's Bizarre Adventure: Battle Tendency: When they first meet, Caesar makes no effort to hide his dislike of Joseph and the rest of the Joestar family, calling Joseph an idiot with weak Hamon ignorant of his own family's legacy and blames Johnathon for the death of Caesar's grandfather William. Needless to say Joseph is not pleased by any of it.
- One Piece: Montblanc Cricket and his family have been ridiculed for centuries because Cricket's ancestor, Montblanc Noland was considered a liar about finding the city of gold, Shandora, and was executed for it, with the king that killed him even fabricating a humiliating fairy tale about it. Ever since arriving on the island of Jaya, Cricket has spent his life trying to find proof that Shandora really did exist and that Noland wasn't a liar. All of his efforts finally end up paying off when he hears Luffy ringing the bell up in Skypeia, confirming that Noland really was telling the truth.
- In A Bug's Life, Flik is terrified of his children being mocked for being associated with him if people find out the "warriors" he brought to defend the colony were actually just circus performers.
- Bandslam: Will's classmates in Ohio used to call him "Dewey" because his father was arrested for driving while intoxicated (DWI).
- The Dark Knight: The Joker mocks Gambol by insinuating that if he does nothing to stop Batman, he won't be able to support his grandmother.
- Monty Python and the Holy Grail: The leader of the French soldiers says that King Arthur's mother "was a hamster" and his father "smelled of elderberries."
- Stand by Me: Teddy shrugs off every insult Milo Pressman throws at him personally, but becomes enraged when Pressman refers to his abusive, Shell-Shocked Veteran father as a looney.
- Bus Joke: A woman enters a bus and wants to buy a ticket carrying her infant son. Bus driver looks away in disgust: "Ew, just sit down. I don't want to see your ugly kid one more second!" She puts her money away, obviously devastated by what the bus driver just said to her. An elderly man notices how upset the woman is and says: "Oh dear, what's the matter?" She says: "The bus driver said something very offensive about my son." He responds: "Now, I wouldn't take that from this guy! You go and give him hell. I'll be holding your monkey."
- Harry Potter: Professor Snape regularly mistreats Harry because of antagonism between Snape and the latter's father, James, even insultingly comparing Harry to James regarding how he perceives their demeanour and attitude. This is despite Harry's personality being much more similar to his mother who Snape was in love with.
- In the seventh Warrior Cats arc, Tree is considered weird by many cats due to his non-Clan name, the fact that he can see and speak to ghosts, and the fact that he doesn't have a normal Clan role but rather holds the role of "mediator", which was created specially for him (and which means he doesn't contribute much during peace times). Kitepaw and Turtlepaw bully Tree's son Rootpaw by mocking Tree, and by comparing Rootpaw to him (which Rootpaw finds embarrassing).
- In the Elementary episode "The Deductionist", there's a disturbance at a home belonging to the sister of a serial killer. It turns out that her neighbors threw rocks through her windows when news coverage of the killer's recent escape and rampage helped them make the connection between the siblings.
- House of Anubis:
- Early in Season One, Patricia shows off her antagonism by listening to Nina's story about dead parents and being raised by her Grandmother, something even Jerkass Jerome took seriously, by snarking that since Nina was now in a boarding school in a different country, her Gran probably wanted to "get rid of her".
- Jerome's big subplot in season 2 was reconnecting with his jailed father and going through major Character Development, helped by Mara's support throughout it all. However, when he wound up cheating on her in season 3, Mara turned on him completely, and wanted nothing more than to hurt him. Because of this, when everyone discovered she was distantly related to a Lord, she used that fact as an opportunity to point out that he's "the son of a thief", an act even her own best friend thought was too far.
- In the Potter Puppet Pals segment "Wizard Swears", Harry Potter calls Neville Longbottom's grandmother a "blast ended skank" when Neville says that his grandmother forbids him from using foul language.
- In Daria, Quinn fears being subject to mockery if people find out that the Cool Loser protagonist is her sister, and spends most of the series fiercely denying they're related. When the truth comes out in the finale, Sandi does indeed begin to mock her for it... but then the other two members of their Girl Posse reveal that they knew the whole time, and were just respecting Quinn's feelings by going along with it.
- Harley Quinn (2019): When Harley's parents reveal to her their intention to kill her for her bounty, Harley attempts to reason with her mother by pointing out that she is their daughter. All this does is get her mom to rant about how people mock them for being the parents of a psychotic criminal with a bad taste in men. Harley feels the need to point out how neither of them are any better due to her father also being a criminal that her mother hooked up with.
Sharon: When you became "Harley Quinn," we became the laughingstock of the neighborhood.Harley: I'm the reason you're a laughingstock? What about Dad being a fucking deadbeat?
- In Phineas and Ferb the Movie: Across the 2nd Dimension, the singer of "Robot Riot" insults the families of the robots, claiming "your momma was a blender and your dad was just a washing machine", and "your sister is a fridge, and you know her light is always on...".
- One episode of Ultimate Book of Spells has the school bullies Lucretia and Borgia mocking Cassie over the fact that that one of her aunts was a traitor who allied with Zarlak and ended up being imprisoned beneath the earth with him. This prompts Cassie to do some investigation, eventually revealing that the aunt is actually a Hero with Bad Publicity who appeared to ally with Zarlak but was actually trying to lure him into a trap.