Wesley managed to be totally oblivious to Fred's feelings for him in Season Five. This came to a head in an episode when he lectured Angel about the latter's failure to notice Nina's interest, while himself remaining totally unaware of Fred's. She eventually resorted to a Forceful Kiss to get the message across.
In Season Three, Cordelia was this way about Angel's feelings for her. Fred seemed to be likewise (re: Wesley's feelings for her) until Gunn later casually mentioned that she knew about them.
Tobias: You know, Mother Lucille, there's a psychological concept known as 'denial' that I think you're evincing. It's when a thought is so hateful that the mind literally rejects it. Lucille: You are a worse psychiatrist than you are a son-in-law, and you will never get work as an actor because you have no talent. Tobias: Well, if she's not going to say anything, I certainly can't help her.
The Colbert Report: Stephen Colbert (the character version of himself) insists that he is completely straight. Evidence to the contrary is dismissed with convoluted excuses when possible, ignored when not (as with the diagram of his brain in which one area was labeled "Repressed Homosexual Urges").
In Crazy Ex-Girlfriend, this is a major part of Rebecca's issues with mental health - it's almost impossible for her to realise what she really needs to be happy because she's so desperate to cling to the tropes of romantic comedies and Disney movies. A particularly painful example occurs in late season two after she finally gets together with Josh but still doesn't feel happy, and starts to wonder whether there's more to her recurring issues with depression than just unrequited love... only for her boyfriend to immediately come in and propose to her, causing her to instantly forget her realisation and devote herself to marrying him. A smaller scale version also occurs in the first half of the first season when Rebecca tries repeatedly to convince herself that she moved to West Covina because she really liked the place, and not because her ex-boyfriend now lives there, because that would be crazy.
To be clear: I didn't move here for Josh, I just needed a change. 'Cause to move here for Josh, now that'd be strange. But don't get me wrong, if he asked for a date, I would totally be like "that sounds great!" Did it sound cool when I said "that sounds great?" Okay, how about now: "that sounds great..." Yes I heard of West Covina from Josh but I didn't move here because of Josh. Do you get those things are different? (No hablo inglés.) ¿Entiendes que son diferentes? Look, everyone, stop giving me the shakedown, I am not having a nervous- ...West Covina!
The Doctor about Martha's feelings for him during series 3. "It's right in front of me and I can't see it" indeed.
Martha and Captain Jack Harkness both, apparently:
The Doctor: Oh! I know what it's like. It's like when you fancy someone and they don't even know you exist. That's what it's like. [runs off] Martha:[stares despairingly after him] Captain Jack: You too, huh?
"Gridlock": All the drivers on the Motorway are aware on some level that they haven't seen any signs from the government and/or the people on the surface for over 20 years, but it takes some serious prodding from the Doctor before they even begin to address the Elephant in the Living Room.
When the Doctor is introduced to Clara's boyfriend, maths teacher Danny Pink, he refuses to accept that a former soldier could be anything else than a sport teacher, and nicknames him "P.E." for all their remaining interactions.
Drake & Josh: Walter and Audrey will always believe Megan to be a saint, in spite of some blatantly obvious hints to her true nature. And even when there is no proof that Drake and Josh were responsible for the shenanigans, they still refuse to believe them due to Megan being the younger sister. Megan exploits this hard in the episode "Peruvian Puff Pepper", getting her brothers in trouble while maintaining her innocence when their parents are around.
In The Finder when Timo is worried about discussing family business in front of Leo, Leo casually mentions that he's "pretty engrossed in his book."
Frasier: Daphne is completely unable to notice Niles' blatantly unsubtle crush on her, even when he's saying things like "I adore you" to her face. It takes Frasier being high as a kite on painkillers telling her to get the truth through.
Rachel is in constant denial about her true feelings for Ross when she's not with him. On the day before Ross's wedding to Emily, she somehow finally figures it out: "Sure, I like Ross, but feelings are really complicated... maybe I am sexually attracted to him, but I do love him... oh my God." When she demands of Phoebe on why she didn't tell her about her own feelings before, Phoebe replies, "Well, it's so obvious to everybody. It's like saying, 'Gosh Monica, you sure like to clean.'"
Ross asks for no strippers at his bachelor party, and after he leaves Joey immediately asks what kind of strippers they should get. Chandler reminds him what just happened, and he replies "Huh. I chose not to hear that."
On top of his book counterpart's general refusal to see positive value in his son Tyrion, Tywin Lannister's last living episode has his daughter Cersei send him to immediate denial mode by confirming certain rumors that he was long aware of but never consciously believed. The rumors themselves should have been obvious and indeed were deduced by Ned Stark - specifically that the Baratheons' black hair is nigh-universally dominant, as is the case with all of Robert's bastards, whereas all three of his supposed children by Cersei are blond like the other Lannisters.
Cersei: You don't know, do you? You never believed it. How is that possible? What am I saying, of course, it's possible. How can someone so consumed by the idea of his family have any conception what his actual family was doing? We were right there in front of you and you didn't see us. One look in the past twenty years, one real look and you would've known. Tywin: Known what? Cersei: Everything they say is true about Jaime and me. Tywin: No. No, no, no, no...
Per his actor Charles Dance, the way Tywin sees things is that his son Jaime was "the handsome apple of my eye" while the other two children are Cersei and Tyrion the whoremongering imp "who, unfortunately, is brighter than the other two put together", so consciously realizing that the rumors were true would have meant admitting to himself that none of his children were okay by his standards and that all three of Jaime and Cersei's children, nominally sired by Cersei's husband Robert, have no legitimate blood claim to either the Iron Throne or to House Lannister.
Shae's jealousy regarding Tyrion's marriage to Sansa despite Tyrion clearly acting as a protector and not consummating their marriage. The fact she feels Varys and Tyrion are exaggerating how precarious her position is, when any passing knowledge of Tywin and Cersei would inform most this is not the case, is very noticeable. Eventually, this refusal to accept how much danger she's in actually forces Tyrion to make a deliberately horrible speech to drive her away and she seemingly takes it at face value.
Though he's shown that he is primarily interested in hunting, whoring, and gambling, Robert is not a stupid man — as evidenced by his Hidden Depths and his occasional status as a Royal Who Actually Does Something — yet in a world where blood so often makes people Colour-Coded for Your Convenience, he is unable to see that Joffrey and his other children bear no phenotypical resemblance to the Baratheon family and in fact have traits that are exclusively Lannister. This could possibly be forgiven if it were the case with only one child and the coloring was evenly spread amongst his other two children like the Starks, but ALL of his children are blond.
Grace Under Fire: In one episode, one of Jimmy's relatives tells to Grace he's gay — but the family insists that he's just shy. This time, he goes so far as to directly tell Jimmy's mother he's gay, but she disagrees and tells him he's just shy.
Played with in Hannah Montana; Miley mentions that she's kissed before, and quickly backpedals prompting Robbie Ray to say "I love our relationship, you pretend you don't kiss boys, and I pretend I believe you."
A very common theme in Hoarders, where people don't seem to notice they're living in squalor. One episode featured a woman who had a lot of dolls. At one point she picks up a small doll that's the size of a soda can and declares that it doesn't take up any space, completely ignoring the 8-foot-tall mountain of toys in front of her.
Barney Stinson from How I Met Your Mother is almost totally self-deluded; not only is he a compulsive liar who believes his own lies, he constantly twists his perception of reality to paint himself and his life as "awesome", no matter how pathetic he actually is. For example, he will invent arbitrary social rules to justify his behavior and claim historical precedents for them, and continually insist they are true, despite their obvious falsehood.
This apparently stems from childhood, when Barney's mother chose to lie to Barney and conceal from him anything that might damage his sense of self-worth. For example, when no one came to his birthday party, she forged a letter from the Postmaster General, claiming he had lost all the invitations. This made Barney unable to accept anything that might damage his overinflated ego. Once, when he amicably broke up with Wendy the Waitress, he chose to believe she had gone crazy and was trying to murder him, rather than face the fact she simply didn't mind not being with him.
Everything you need to know about Barney can be seen in an episode in the sixth season: Zoe sets Ted up with her attractive cousin "Honey", and Robin and Barney both relate their own versions of the date to Marshall; in Robin's presumably more truthful account, Honey is fascinated by Ted and blatantly flirts with him, while Barney desperately attempts to hit on her and she politely ignores him. While eventually, Barney does leave with her, it's only because Ted is much more interested in Zoe and lets him; in Barney's version, Ted bores Honey by droning endlessly about architecture, and she is virtually ripping off Barney's clothes the whole time. When Marshall points out the difference in the accounts, Barney angrily insists his is true.
The entire group is guilty of this and later seasons have them confront this as part of their Character Development. Barney finally acknowledges that Bob Barker is not his father and actually seeks out his real dad. Ted and Robin realize that they do not have a future as a couple and that by remaining roommates they stifle any chance of having serious romantic relationships with others.
It's Always Sunny in Philadelphia practically runs on this trope as the four younger members intentionally ignore their flaws and shortcomings:
Dennis refuses to admit that he runs a failing business, he isn't as smart as he thinks, and in general that he is just as much of a loser as the others.
Dee refuses to admit the fact that she is a terrible actress and is a rude, crude, and white trash alcoholic waitress.
Charlie refuses to acknowledge the fact that the Waitress hates him and will never love him.
Mac is probably the biggest example of this trope. He refuses to acknowledge the fact that his mother couldn't care less about him, he is terrible at karate, he isn't a badass, he isn't heterosexual, his friends openly despise him, and that he isn't as devoutly religious as he believes himself to be.
Kamen Rider Gaim: After the Inves Plague breaks out the people of Zawame City turn against the Beat Riders while worshiping Bravo as a hero, while conveniently forgetting that Bravo himself was responsible for one of the biggest Inves rampages. This is sadly justified thanks to mob mentality and the fact that Kaito sent out some Inves when he got called out by the mob.
Hyacinth in Keeping Up Appearances remains oblivious to the fact that everybody wants to avoid her because she's totally obnoxious. She does this not only in the face of people practically running away from her — her Lack of Empathy extends to not noticing any kind of social cues other than ones related to class snobbery — but even filters it out totally when Emmett goes so far as to tell her a part of his opinion about her with Brutal Honesty. It may be he only dares to do so because he has some idea she won't process it.
In Lie to Me, Gillian readily accepts her husband's feeble excuses about having to work late, even though her job is based around the ability to tell instantly when someone is lying. It is later revealed he was going to AA meetings and the woman was his sponser.
In a first-season episode of Mad Men, gorgeous Joan's female roommate makes a very obvious sexual come-on. Joan pretends that she doesn't get it, the roommate pretends that Joan isn't pretending, and the incident is forgotten about.
In The Mighty Boosh, whenever Vince says or does something suggestive towards Howard (which is quite often) Howard will either walk away or awkwardly change the subject, totally ignoring it.
In Peaky Blinders, Tommy (ofallpeople) undergoes this whenever Grace is involved, seemingly ignoring or pretending to forget that she was originally The Mole who sold him out to his worst enemy. Polly calls both him and Grace out on it, informing the latter on her wedding day that even if Tommy has chosen to forgive Grace, the rest of the family have not forgiven or forgotten what she did and it's only because they love Tommy they're willing to pretend for his sake, with the implicit threat that if she ever tries it again, Polly will deal with her.
Guy of Gisborne from Robin Hood chooses to ignore the mounting evidence that Marian is in cahoots with Robin Hood. By the final episodes of season two, he's in complete denial.
Gul Dukat on Star Trek: Deep Space Nine. His imagined friendship with Captain Sisko escalates to ridiculous levels throughout the series, to the point where he chides Sisko for being so obtuse about his feelings while on the opposite sides of a battle line or in the middle of a no-holds-barred hand-to-hand fight. In fact, you could probably form a whole section on all the things Dukat pointedly ignores. (Although, from what little has been revealed of the Cardassians, that may be how they express friendship, or he may be doing it just to annoy Sisko.)
In Strangers with Candy, the homophobic Principal Blackman is the only one who doesn't know that Chuck and Geoffrey are lovers. At one point he catches them in the school basement and happily accepts the explanation that Chuck is showing Geoffrey the furnace system, even though Geoffrey has his trousers round his ankles.
In The Suite Life of Zack & Cody movie, Zack not only blatantly ignores two signs, he reads out loud what he wants them to say.
Research facility sign: No unauthorized personnel. Absolutely no admittance! Zack: "Come on in. All are welcome." Perfect. Loading bay parking sign: Absolutely no parking here. Zack: "Absolutely no parking here except for Zack."
The last one comes back to bite him as a cargo crate is dropped in the exact spot he's parked in the second he leaves the car he pestered his brother for, crushing it horribly.
Elena from The Vampire Diaries is a darker example of the trope. While she may view Damon as a Jerkass Woobie, Damon has done actions that cross the Moral Event Horizon to her friends including trying to kill Caroline and Bonnie, killing her brother Jeremy (he got better), killing Lexi, turning Vicki into a vampire who had to be staked, and forcibly turning Bonnie's mother into a vampire. Basically, even if you ignore the large number of random people he's killed and continues to kill when he's in a bad mood, he's done enough to the people Elena is supposed to care about that her fondness for him requires mountains of this trope.
Stuart: Well, I hoped she'd have figured out our situation by now. I have been dropping little clues. Freddie: Yes. Like living with a man for 48 years.
What We Do in the Shadows (2019): Despite being a vampire himself, Lazlo refuses to believe that ghosts are real and mocks his wife Nadja for believing. When put face to face with a ghost he pointedly ignores it for as long as he can.
