Angel: An odd example: the demon Sahjahn spends a good chunk of the third season working against Angel, but when the two finally meet, Angel has no idea why Sahjahn hates him, driving the latter to disappear in fury. Of course, Angel was a bit justified in this: Sahjahn's beef was a future event that Sahjahn knew about from a prophecy. A prophecy that he had even rewritten himself centuries before, so it was basically impossible for Angel to know about it. Granted, existing outside of time might mess with his perceptions a bit, but, really, Sahjahn's expectations just seem a little high.
The Bill: Commonly inverted, such as a man who was adamant that Dave Quinnan had changed his life. Quinnan had to ask someone to check the archives because he didn't remember him. Turns out that he was once arrested for disorderly behavior, processed and released. Being on the receiving end was what inspired the man to get on with his life, but to Dave, it was a normal Tuesday.
Another time a sixteen-year-old girl was stalking Sergeant Cryer for half of the episode. She wanted to know what he could remember about finding a baby girl sixteen years previously, because she wanted to know who she was. He didn't remember much.
Blackadder: Played for laughs in the final episode of the second series, which includes a rare example of the Big Bad being on the receiving end of this trope. Prince Ludwig seems surprised that Blackadder, Melchett and Queenie do not remember him, and then proceeds to remind them of a time each of them had met him—examples which vary from obscure to downright ridiculous (/depraved. Looking at you, Melchett).
Blade: The Series: Marcus Van Sciver has spent decades plotting revenge against the pureblood Damek, who brutally murdered his wife in front of him and then had Van Sciver sent to a bunch of feral vampires, who ended up turning him. Eventually, Marcus confronts Damek and starts a fight. Right before Van Sciver kills him, Damek laughs and tells him that he can't even remember Marcus's wife or him. Justified in that he is centuries old and, presumably, has been killing people all this time.
During Anya and Xander's wedding, a demon shows up disguised as Xander from the future to destroy everything, most horribly making it seem like Xander doesn't love Anya. It turns out this demon was actually once an adulterous human whom Anya punished back in her days as a vengeance demon. Anya, who had probably done horrible things to thousands of them (or more) in her life time, has no memory of this. This is an unusual case, since Anya comes out as sympathetic rather than the demon.
A subversion occurs in the episode "Lies My Parents Told Me", where the murdered family member actually isn't just another victim.
Robin Wood: Oh, I know more about you than you think, Spike. See, I've been searching for you for a very, very long time. Ever since you killed my mother. Spike: I've killed a lot of people's mothers. Robin Wood: Yeah. You'd remember mine. She was a Slayer.
This happens often with Spike in season 7 of Buffy and season 5 of Angel. He'll be honestly trying to help someone, and the rescuee wants nothing to do with him because he murdered their family—something Spike has no memory of.
In a different subversion, Spike is captured and tortured by a crazed Slayer who believes that Spike killed her parents. It is later confirmed that Spike was not responsible, but it doesn't make him feel any better about it, since he's killed so many people that it's not much of a consolation that he wasn't responsible for these particular deaths.
Buffy herself is a heroic example of that trope: Riley is praised for single-handedly catching 17 creatures.
Buffy: Wow. I mean, that's...seventeen.
Riley: Buffy. When I saw you stop the world from, you know, ending, I just assumed that was a big week for you. Turns out I suddenly find myself needing to know the plural of "apocalypse".
When Andrew first appears on the show, he says that the Scoobies stopped him from using flying monkeys to attack a school play. The Scoobies have no memory of this and, in fact, it did not appear on screen.
Charmed: Has an episode where Heel-Face Revolving Door Belthazar is being hunted by a good witch because he killed her husband. Because he is currently face, he is helping her hunt down the demon he thinks is responsible. After the accusation, he doesn't even know for sure if she is right or not.
In the pilot episode of Covert Affairs, this is Auggie's response to Annie's description of her first day on the job.
Annie: I saw a man get killed today, I lied to a federal agent, I was shot at...
Auggie: Or, as we call it, Thursday at the Agency.
Criminal Minds: An episode had Hotch and Reid interviewing a serial killer on death row. When Reid asks the inmate why he killed a woman named Sheila O'Neil, the killer nonchalantly mentions that Reid's going to have to be a lot more specific with details regarding the victims, as he can barely remember them.
Chester Hardwick: Truth is, they meant nothing to me. They were toys, a diversion, and from the moment I decided to kill them, they were dead. They begged, they cried, they bargained, and it didn't matter, because they didn't matter.
John Oliver, July 25, 2013: "In the stock market, that's what's known as 'insider trading'. In the commodities market, it's known as simply 'Thursday'."
In CSI: Miami one case involved the murder of a man at a high-school reunion. It turned out the killer was a victim of the man's bullying, his entire body was wrapped with duct tape, including his mouth and was stuffed in a locker. The incident left permanent physical scars all over his body, as well as mental, though the killer, when meeting up with the bully, calmly and politely asked for an apology, assuming he had matured into a nicer person. Not only did the bully refuse to apologize but he admitted he didn't even remember the incident at all, only giving a blunt "get over it". This threw the killer over the edge and knocked him dead with a wine bottle.
Degrassi: In a season six episode, Alex joins the lacrosse team and is promptly cold-shouldered by one of the other players for what Alex assumes is no reason. Turns out that, years earlier, Alex tripped her and broke her leg and nearly blinded her with a laser pointer.
Doctor Who: This mentality really gets under the Doctor's skin. In "The Vampires of Venice", he promises to take apart Rosanna's empire piece by piece, not just because she killed one of the Doctor's friends, but because she hadn't even bothered to learn her name. Note that Rosanna probably remembers killing that person, she just never knew the girl's name to begin with.
The new series has characterized the Doctor's adventures as being this trope from the perspective of his foes.
"Margaret": From what I've seen, your funny little happy-go-lucky life leaves devastation in its wake. Always moving on 'cause you dare not look back. Playing with so many peoples' lives, you might as well be a god.
Doctor: There was a goblin, or a trickster, or a warrior. A nameless, terrible thing, soaked in the blood of a billion galaxies. The most feared being in all the cosmos. And nothing could stop it or hold it or reason with it. One day, it would just drop out of the sky and tear down your world.
River: You make them so afraid. When you began all those years ago, sailing off to see the Universe, did you ever think you'd become this? The man who can turn an army around at the mention of his name? "Doctor", the word for "healer" and "wise man" throughout the Universe; we get that word from you, you know. But if you carry on the way you are, what might that word come to mean? To the people of the Gamma Forests, the word "doctor" means "mighty warrior". How far you've come. And now they've taken a child, the child of your best friends, and they're going to turn her into a weapon just to bring you down. And all this, my love, in fear of you.
In "A Good Man Goes To War", the Doctor has a benevolent version, where he saved someone's life as a child and she devoted her life to meeting him. As they don't come face-to-face until she's been mortally wounded helping him, he pretends to remember them running together. It was a pretty safe bet. Being a time traveler, it's entirely possible the Doctor has yet to save her.
According to Gareth Roberts, an early draft of "The Lodger" featured the classic series monster Meglos as the villain—the punchline being that the Doctor would have no idea who he was, even when reminded.
Everybody Loves Raymond: In one episode, Marie relates to Debra the origin of the big wooden fork and spoon that had been background props hanging on the kitchen wall for the entire series: they were a wedding present that both she and Frank hated, and which each felt the other should be responsible for returning. The argument grew into their first big fight as husband and wife, and culminated in Frank spitefully nailing the spoon to the wall, and Marie retaliating with the fork. Since then, Marie says, every time she enters the kitchen she sees the fork and spoon and remembers that horrible fight. At the end of the episode, inspired by her own advice to Debra, she pronounces to Frank that she is "[rising] above 45 years of pettiness!" and taking the fork and spoon down...only to discover that they've been up there so long they've left their silhouettes on the wallpaper. She angrily puts them back up and storms out. For his part, Frank stares at the utensils for a moment, then wonders, "When did we get those?"
In another episode, Raymond and family are attending the wedding of a girl Raymond knew in college. It turns out that Raymond went on a date with her once, and at the end of the night he didn't walk her to her front door, as he was more concerned about keeping an eye on his father's car. Raymond still feels incredibly bad about this, even though everyone else thinks he is just being neurotic. Finally, Raymond gathers his courage and apologises to the girl. Sure enough, she doesn't remember the incident at all.
Farscape: In The Hidden Memory, Aeryn confronts Crais, reminding him of how he declared her "irreversibly contaminated," thereby practically ruining her life. He does not remember the incident, and it is not until he sees her face that he recalls who she is, albeit with some difficulty. A bit more justified than many cases, since he was following standard procedure and it was the same day his brother died and he went rogue to avenge him.
The Flash: In the series pilot, Barry Allen's brother is ambushed and killed by the guy he put in prison years before. After becoming the title superhero, Barry confronts the killer and tells him why he's chasing him. The killer asks for clarification as he kills "a lot of brothers".
Friends: In "TOW the Rumor" Rachel's old high-school classmate Will (played by Brad Pitt) reveals that she was so mean to him in school that he founded the "I Hate Rachel Green Club". Rachel doesn't even remember him.
Game of Thrones: When Arya gets her revenge on Polliver, she starts by repeating the words he said to her friend Lommy when he killed him. Polliver has absolutely no recollection and just looks bewildered at the words spoken by the crazy child standing over him. It's not until she repeats his words about picking his teeth with her sword that he finally figures out who she is.
Heroes: Sylar's father. When Sylar says that his father killed his mother, Samson barely remembers.
House: The title character, being insane, often invokes this trope by failing to recall actions that any other physician would consider...well, insane.
Defied by House, himself, in an episode he has reason to doubt his medical judgement and asks Wilson to keep him from doing anything more dangerous than usual to his patients. At one point, he runs an idea past Wilson, and is forced to ask him if his plan is "Regular crazy, me crazy, or me out of my mind crazy."
Wilson: ...It's illegal! People go to jail for that; pay huge fines!
Ted is talking about the night that he stole the blue French horn for Robin, prompting Barney's revelation, "Oh right, that was you." When a shocked Ted asked how he could forget as it was a big iconic moment in all of their lives, Barney shrugs and replies, "For you maybe. I got a lot of stuff going on."
Another example of Barney is the episode "The Bracket", where the group tries to figure out which of Barney's jilted lovers is trying to get revenge on him. When they finally track her down, she isn't even on their newly-created Bracket list of his top jilted lovers. Barney is horrified that he doesn't remember a woman he slept with and goes up to her and apologizes both for not remembering her and for whatever he did to her (he once sold a woman; he's done some pretty horrible things). Averted in that they had never slept together and the girl had no idea who Barney was either.
A comedic example occurs when Marshall sees a contract that Barney's company has with Portugal that if they, "are not executed precisely, we will be at war with Portugal." To which Barney responds, "Please, that's a Tuesday for me." He then grabs the contracts and shreds them.
In an episode of Married... with Children, a fat woman faces Al Bundy for making fun of her. He has a lot trouble remembering her, even as she claims he had called her a giant seal.
The League of Gentlemen: Papa Lazarou has a book entitled The Book of Wives that catalogs every woman he's ever snatched so he can keep track of them all. He consults it to find out who Brian's wife was: she was Geoff's.
"Do you know, I can't even remember if she's alive or dead!"
LOST: Sawyer finally encounters the man that ruined his life by driving his father to kill Sawyer's mother, and then kill himself (through a routine con), only for the man to say that he ran that con dozens of times and that it was Sawyer's father who took it badly. His callous indifference gets him killed by Sawyer.
Merlin: This Trope is mentioned by name in the DVD commentary for episode 2x11. Alvarr's confrontation with Uther before he is imprisoned is, for him, the culmination of years of fighting against his regime, but to Uther he is just another sorcerer to be executed.
Mystery Science Theater 3000: In the episode "The Brain That Wouldn't Die", the film opens in an operating room, prompting Mike to snark: "Just a normal Tuesday for Cher".
Ned And Stacey: In the pilot, Stacey comes to Ned's apartment to confront him about him stealing a speech from her and using it out of context in a commercial.
Stacey: Remember me?
Ned: I'm not sure.
Stacey: Then let me remind you. I'm the person you exploited without a trace of conscience.
Ned: You're gonna have to be more specific.
Once Upon a Time: Invoked in "The Doctor": a young Regina takes two other people into the vault full of the hearts her mother has (literally) ripped outnote Ripping someone's heart out doesn't technically kill them, destroying it afterward does. When asked who they belong to, she replies her mother ripped out too many hearts and destroyed too many lives for anyone to keep track of them all.
Later in the same episode, someone breaks into a vault of Regina's, and takes a heart from it. Regina admits that she does not know who it belonged to, as she has taken too many. To her credit, she recognizes the irony and appears appropriately disgusted with herself.
Appears in another episode, as a form of Black Comedy. Rumpelstiltskin, who has destroyed more lives than Regina or her mother, is forced to ask other members of the town for help. David is only one willing to help him, and the following (paraphrased) conversation takes place:
David: Do you remember turning a butcher into a pig?
Rumpelstiltskin:[genuinely taken aback] No, I can't say I do.
David: Well, that man does. It was his father. I'm beginning to see why no one wants to help you.
Revolution: Invoked by Charlie in Episode 2, but it's Monday, not Tuesday.
This used to be a running joke when Norm MacDonald did the news. One example: "Tomorrow marks the beginning of Chanukah, or the Festival of Lights, in which Jewish people around the world celebrate the re-dedication of the Temple in Jerusalem...or as non-Jews would call it, Wednesday."
Scrubs: In the season 8 episode "My Finale", Doctor Cox uses this to express his contempt for JD. JD is leaving Sacred Heart hospital for another job, and wants to get a heartfelt goodbye from his mentor. Instead he is met with this—"Newbie, I know that you want this to be a special day for the both of us [...] I'm real sorry there, Newbie, but this is not a 'special' day for me, it's just...a day." That said, when JD gets a resident to bad-mouth him to Cox later, Cox shows his true feeling about the matter.
The Seinfeld episode The Baby Shower has a double example, when George tries exorcise an old grudge with a woman who snubbed him, but chickens out; and a unidentified woman carries it to completion with Jerry.
Southland: This trope frames the episode "Wednesday", in which the narrator announces at the beginning: "Cops wake up every morning different from the rest of us. Our worst nightmare is just their Wednesday."
Stargate SG-1: The beginning of the episode "Cor-Ai" goes like this. A man tries to put Teal'c (the recently reformedDragon of Apophis) on trial for killing his father. It takes Teal'c a while to even remember visiting the planet. In this case, though, both are portrayed sympathetically, and Teal'c is remorseful even when he doesn't recall what exactly he did.
It turns out that Teal'c killed the man's father so that Apophis wouldn't wipe out the tribe. The tribe runs and hides when the Goa'uld come, but are slowed down because they take care to help the slower members—the elderly, the crippled, etc.—escape as well. When Apophis ordered Teal'c to execute one, he chose to kill the elderly, one-legged gentlemen, because his death would make it easier for the rest to run away and hide next time. While Teal'c knows he killed the crippled man to allow the rest of the tribe to escape, Apophis thought Teal'c did it For the Evulz, was satisfied, and didn't order any more killings. When you see the flashback in its entirety, the man is quite clearly signaling Teal'c to kill him. Teal'c did that kind of thing quite often in a mostly unsuccessful attempt to moderate his master's evil (as Bra'tac did before him), before being convinced that an open rebellion against the Goa'uld could succeed. Hence his inability to remember this specific instance.
Star Trek: Deep Space Nine: The episode "Duet" has Kira confronting the Cardassian war criminal Gul Darhe'el about his brutal actions during the Cardassian occupation of Bajor. At one point, Darhe'el simply says "What you call genocide, I call a day's work." Though it turns out he's actually Aamin Marritza, Darhe'el's assistant, since the real Darhe'el died years earlier, and is posing as him and flamboyantly invoking this trope in an attempt to make Cardassia own up to their brutality and appease his own conscience.
The episode "One More Unto The Breach" reveals that Martok was denied an officer's rank by Kor. Martok holds a grudge against Kor for this for years, but Kor doesn't remember the specific incident.
Studio C: In "Evil Memory Lapse", Professor Murdock is confronted by a woman he doesn't recognize, even though he killed her father and they used to have something "special". He also doesn't remember trying to get a tikiman, even though he's killed 10,000 people trying to get it.
In Suits, Mike Ross goes to confront the lawyer who gave his grandmother a crap deal after his parents died in a car crash. The lawyer has no idea who his parents were even after Ross names them, because he gave so many people the same kind of crap deal over so many years.
In a later episode, the lawyer turns this around on Mike by pointing out that Mike is now what the lawyer used to be.
Supernatural: Cole spends more than 12 years of his life hunting Dean after he sees Dean murder his father. When he finally catches up with him in "Reichenbach", Dean (who isn'thimself at the moment, being a demon and all) says:
Dean: Well, hey, I'm not saying I didn't slice-and-dice your old man, I'm just saying that he wasn't the first, and he wasn't the last, and they all just kinda get blended up.
It later turns out that Dean does remember the incident, though it's not clear whether he had to think about it or if he was pretending to have forgotten to make Cole feel worse.
The Fresh Prince of Bel-Air: The bully who beat Will up and got him sent out to Bel-Air in the first place doesn't remember beating Will up when he comes back to Philadelphia. He only remembers when Will bops him on the head with his basketball...which prompts the revelation that he's reformed himself.
Throwdown with Bobby Flay: More of a Real Life example: in the "Rematch on the Grill" episode, Bobby was having an epic three-course cook-off with three competitors that he had beaten in the past. Near the end, Tobin Ellis, a bartender who Flay had defeated in Las Vegas who had come to Florida to redeem himself, stepped out of the crowd and started talking to the chefs the way Bobby does when he challenges someone. Bobby thought he was just some audience member asking for food until someone explained who he was.
The Office (US): The episode "Drug Testing" has an example of a subversion. At one point Dwight is chatting with the urine tester, and asks if she remembers one time when he was tested. She starts to invoke this trope, but then Dwight points out that his was green. She immediately remembers him.
The Twilight Zone gives us "Death's-Head Revisited", where a Nazi officer revisits a concentration camp seventeen years after the war. He runs across a former inmate, and a battle of wills begins. At the end, the officer remembers killing the inmate the night the Allies raided the camp - the implication being that he'd killed so many people that he simply forgot until then.
The Wire: Avon Barksdale, the Big Bad of the Barksdale Organization, and his Brute Wee-Bey have a darkly comedic version. At the end of the show's first season, they're both sent to jail. In the second season, a corrupt prison guard named Tilghman spends a great deal of time harassing Wee-Bey, and then brusquely refuses Avon's attempt to make a deal, which no one does to Avon. Eventually Wee-Bey hears the reason why Tilghman won't let up on Wee-Bey: Tilghman is related to someone that Wee-Bey killed on Avon's orders. Avon doesn't remember a thing about it, not even when Wee-Bey starts trying to supply details to jog his memory. (By the time Avon and Wee-Bey are in jail, their organization is responsible around twenty murders in the past two years alone. Is it any wonder Avon can't remember them all?)
Avon: What's up with this motherfucker? Wee-Bey: You remember LaDonte? [Avon squints in confusion] Burner from over in the Poe Homes, finally caught him over in the parking lot after school? Avon:We did that? Wee-Bey: Tilghman is LaDonte's cousin or some such. He found out I ate the charge for killing him, now he busting my chops. Avon: LaDonte? [shakes head in confusion] I can't even remember that one. Need a scorecard to keep up with your lethal ass.
Ironically enough, Wee-Bey may not even have been responsible for that crime. When Bey was caught, his lawyer got the prosecutor to agree to take the death penalty off the table in exchange for a full confession...and Bey then tried to take responsibility for every killing ever committed by anyone in the Barksdale gang. While the cops knew that some of those were committed by others, who knows how many crimes Bey "ate the charge" for that he didn't commit. LaDonte's murder could have been one of those.
Without a Trace: In the episode "Legacy", the events of the episode are set into motion after a family happens to run into the man who broke into their house, tied up the dad and brutally raped the mother ringing their shopping at the store...and he gives absolutely no indication of having recognized them. This, coupled with the fact that they tried to ignore the incident to a clearly-unhealthy degree, results in the father's disappearance and the mother killing her son's drug dealer after the latter made an ill-timed pass at her. When the father is found, he had just murdered the rapist.
In You're The Worst, Jimmy told Becca (his ex) "we haven't made love for the last time" at her wedding. It causes her to struggle with her feelings for Jimmy for the entire season, which culminated in her going to Jimmy's place to have sex. Jimmy's reaction when she reminded him of his words (which he totally forgot):