Parting Words Regret

"Why was I always such a brat? Why did I always fight her? And I never said 'I love you!' Now I'll never get to! Never!"

A character has been Killed Off for Real. One of the survivors recalls the last conversation they had with the deceased, and wishes they had chosen their words more carefully. Maybe they said something hurtful, perhaps even wishing them harm and never got a chance to take it back. Maybe the conversation was about something mundane and trivial, and they wasted to opportunity to express their true feelings to the person. Whatever the case, they look back on the incident with regret.

Sometimes inverted where the dying person feels the regret. Related to Never Got to Say Goodbye and I Wished You Were Dead.

Anime and Manga

 * In Fruits Basket Tohru regrets not saying "take care" before her mother left on the day her mother died.
 * In Bleach Orihime regretted not giving her brother her usual fond farewell when he left for work on the day he died because they had an argument earlier. When her brother came back as a Hollow and was defeated/purified by Ichigo and Rukia, Orihime took the chance to say farewell to his departing spirit.
 * Soul Chess: "Look if you want to go and get yourself killed that's fine by me. Don't expect me to be at your funeral."
 * In the dub of Digimon, Ken yelled at his older brother that he wished he'd dissapear—said brother is then hit by a car.
 * In Attack on Titan, wasn't well behaved before  died.
 * In My Hero Academia Kota forgot to apologize to Midoriya, and with the knowledge Midoriya is in danger, fears this trope will play out.

Comic Books

 * Victor Alvarez the second Powerman after Luke Cage gave up the name has this in his origin story. Victor's parents were getting ready to divorce, and Victor was upset that his dad wasn't trying harder to make the marriage work. Victor accused his father of not being strong enough to fight for his own family. When Victor saw how much his words hurt his dad, he immediately tried to apologize...and that's when the bombs Bullseye set in Hell's Kitchen exploded. Victor survived but he could never forget his dad's wounded expression.
 * One Batman story had a flashback that showed eight year old Bruce getting angry at his parents for some reason and saying that he hated them. In an effort to cheer up Bruce, his parents took him to watch Zorro the very next night. Bruce was about to apologize to them on the way home right when they entered Crime Alley...

Film
""I can't help thinking about...the last thing I said to him. He tried to tell me something important, and I threw it in his face.""
 * In the 2010 Karate Kid Mr. Han recalls he was arguing with his family before they died. He doesn't remember what it was about, but he hopes it was important.
 * In the first Spider-Man film Peter laments the argument he had with Uncle Ben, just hours before Uncle Ben gets shot.

"Norman Osborn: I've been like a father to you... be a son to me now. Peter: I have a father. His name was Ben Parker."
 * In particular, the very last thing he said to Uncle Ben before he was shot, was yelling at him to stop pretending to be his father... something which visibly upset Ben. This actually comes back at the end of the movie in a more redeeming way.

Literature

 * In Harry Potter and The Goblet of Fire, after Harry and the Weasley children have a brush with Death Eaters, Mrs. Weasley mentions that she'd never forgive herself if Fred and George had died when the last time they'd talked she was chewing them out for their bad grades.

Live Action TV
"Red: I didn't say "I love you," or even "See you later." No, the last thing I said to her was "Show me tail lights." Eric: ...Dad, the last thing I said to Grandma was "It wouldn't kill you to be nice once in a while." But I guess it did, because then she died."
 * In Burn Notice, Fiona and her sister had a fight before her sister was killed in a shooting and she's always regretted it. Her sister's death motivated her to join the IRA.
 * Inverted in How I Met Your Mother. After  dies, his family decides to have the funeral eulogies based around the last words he said to each of them.   gets distressed because the last thing   said to him was that he should rent Crocodile Dundee 3, whereas everyone else has profound, meaningful moments to talk about.
 * But then it turns out there was a rather touching message waiting for  on his voicemail... And he still goes with the Crocodile Dundee story when talking at the funeral.
 * An episode of Home Improvement has Jill telling her father that she was too sick for him to visit. He dies shortly thereafter, and the rest of the episode focuses on how Jill regrets lying to him.
 * In Criminal Minds, Elle's father died when she was eight and the last thing she said to him was "I hate you, Daddy!" (she was angry that he didn't have time to teach her to ride her bike). Years later, she still regrets this.
 * In the Cold Case episode Disco Inferno, the father of the murder victim the detectives investigate confesses to this, for the last words he said to his son, in reaction to said son's future life choice, were "I... renounce... you." The son died later that night.
 * In the episode "Shuffle, Ball Change", the victim and his brother got into a shoving match that resulted in the brother injuring his knee, possibly derailing his wrestling career. Their infuriated father told the victim, "God help you, Maurice". The boy disappeared soon afterwards, leaving the father thoroughly haunted by the thought that his son had run away from home thinking that his father hated him, and even more torn up when he learned that his son had in fact been murdered, and that either way, those were the last words that he said to him.
 * In That '70s Show, Red's mother dies as Eric is driving her home. Because she was being a heartless crow (like usual), no one had anything good to say about her, but were still heartbroken when she was gone.

Music

 * The song "The Last Thing She Said" is all about this trope, except that the woman with regrets is actually the one in danger of dying.

New Media

 * It turns out the in Conquering the Horizon are people. Evelyn killed one, Hsthressis, and ate her. Hsthressis and her mom had a fight before this.

Video Games

 * The World Ends With You:
 * Late in one route of Blaze Union, Siskier and Jenon playfully make fun of each other while rescuing Dude in Distress King Ordene before splitting up in hopes of getting him out of danger faster, culminating in Siskier calling Jenon an idiot. Jenon winds up gravely injured, then falling into and being washed away by the castle waterways. Siskier discusses this with protagonist Garlot while the two are trying to find Jenon later on.

Webcomics

 * Discussed in this Xkcd comic.
 * In Get Medieval, Asher spends the whole story arc regretting that his last words to his girlfriend before ending up stranded on medieval Earth were to tell her to buy cat food.
 * In this Buttersafe comic, a sailor realizes ahead of time that this is the last time he'll ever see, and somehow he still manages to screw up his goodbye.

Western Animation
"Homer:"Yeah, you probably should have said something romantic, like 'I love you'""
 * In The Simpsons Ned Flanders regrets that the last thing he said to Maude was "No footlongs."

""I yelled at him, Mom. He grounded me and I wouldn't listen. The things I said--!""
 * Implied with Homer and his mother Mona. During Mona's final appearance, Homer blew up at Mona for never being there for him and putting her various agendas ahead of him. Later that night, Homer cooled down and made an apology card for her. Only to find that she died sometime in the night.
 * In Gargoyles, after Demona (apparently) sacrifices herself to save Angela, the daughter she had just recently met, Angela immediately regrets that the last thing she said to her was that she hated her.
 * In Batman Beyond, Terry bitterly regrets his last conversation with his father:


 * Batman the Brave And The Bold has