I didn't want you around
Those pretty faces always made you
Stand out in the crowd
But someone picked you from the bunch
One glance was all it took
Now it's much too late for me
To take a second look"
Before the crisis, the character is perfectly fine being Just Friends or totally platonic bickering partners with another. But then, that other character gets romantically involved with an interloper, causing their not-at-all love interest to suddenly feel the sting of their absence. Once they finally admit to themselves their feelings, the Romantic False Lead's got hell to pay.
In some works, this is the cue for a Relationship Upgrade. In other works where Status Quo Is God, the envious one will stubbornly refuse to come clean and revert back to her "friend" self once the romantic complication is out of the picture. It's a Aw Look She Really Does Love Him moment — but a hidden one. This arc is especially common when the jealous one is a Tsundere.
Sometimes this trope comes into play after a couple has broken up, with one side having convinced herself that she's over him until seeing her ex with a vixen causes her to gnash her teeth.
If one partner isn't in denial and deliberately stages such an incident to make the other jealous and admit her feelings, he's pulling an Operation: Jealousy. Sometimes overlaps with Unrequited Love Switcheroo — a flip between which lover's love is unrequited. The writer might need to Derail the Love Interest if the new love is working out too well for the plot to continue.
- In Runaways, Nico finally realizes that she does feel something for Karolina after the latter ends up in a relationship with Xavin. Inverted in a later arc, when Nico realizes that she doesn't really love her then-boyfriend Victor after finding that Lillie's attempts to flirt with Victor just annoy her rather than really angering her.
- Elizabeth of For Better or for Worse had this problem:
- One plot arc involved her breaking up by proxy with Anthony right before the school dance, only to get insanely jealous when the friend she'd had deliver the news felt sorry for him and opted to take him instead.
- Infamously, this plotline was later echoed and writ large when Anthony got married, with Liz lamenting that she should have been the one he'd chosen instead. Therese, for her part, was openly cool and distrustful towards Liz; the comic treated this as though she was being snobbish rather than rightly clocking her as a potential threat to her marriage.
- Later on, Anthony asked Liz to 'wait for him' while confessing how miserable he was in his marriage... and also how he'd blatantly lied to his wife, convincing her to have a child by promising that he'd be the one to take care of them, only to be shocked when Therese expected him to keep his word. Their marriage ultimately fell apart, with Anthony and Elizabeth's wedding serving as the final arc of the series.
- Blast from the Past has Alicia Silverstone go through this again as Eve, realizing her feelings for Adam when he's in the middle of dancing with a pair of blondes and he cheerily waves at her.
- In Clueless, Cher realizes how much she loves Josh when she finds herself getting angry with Tai after the latter won't stop talking about how she's meant to be with him.
- This trope is essentially the plot of My Best Friend's Wedding. When Julia Roberts's Just Friends buddy of a decade announces he's tying the knot, she secretly tries to break up said wedding so that the groom will marry her instead.
- In Plan B, Bruno broke up with Laura a year ago out of boredom but after seeing her happily together with another man, he becomes jealous enough to come up with the titular plan to win her back. However, he realizes at the end of the film that not only was his plan a completely stupid one, but he no longer wants to get back together with her after falling for someone else.
- Avril Lavigne's "Sk8er Boi", the former Trope Namer, is a song about a girl who is in denial about her love for a boy she knows until he's already been claimed by another (and become a superstar musician with his girlfriend while she's become a lonely single mother). Unusually for arcs invoking the trope, she doesn't get him in the end. Here the rival is the song's point-of-view character, possibly the artist herself — more normally we follow the fate of the girl having the epiphany.
- "Judy's Turn to Cry" by Lesley Gore (the sequel to "It's My Party (And I'll Cry if I Want To)") has the singer get Johnny back this way. She starts dancing with another guy and it makes Johnny realize that he still wants to be with her.
- "Taken" by One Direction:
You only want me when I'm taken
- Paramore's "Misery Business" is an extended musical Take That! to the former girlfriend in this situation, including calling her a whore. Given that, according to Hayley Williams, it's based on events from her own life, it's a possible twofer...
- Toby Keith's "How Do You Like Me Now?" is about a guitarist/songwriter gloating through the radio at the girl who rejected him in high school and went on to marry some rich guy who never has time for his family. The video, on the other hand, makes it clear that his ex-crush still isn't very impressed with him.
- "Wasted Times" by The Weeknd, addressed to an ex-girlfriend (commonly believed to be Selena Gomez).
Even though you put my life through hell
I can't seem to forget 'bout you
I want you to myself
- In The Muppet Show, Kermit was usually very disinterested in any of Miss Piggy's advances towards him; but whenever she became infatuated with a male celebrity guest, such as Christopher Reeve or Peter Ustinov, he would become jealous. She tried to invoke this trope when Avery Schreiber was the guest, but it didn't work (Scooter warned Kermit of her scheme ahead of time).
- In Dog In A Manger by Lope de Vega, the secretary Theodoro has a love affair with one of Countess Diana's (his employer) maids. She discovers this, which forces her to reflect on her own feelings for him and kicks off the entire plot. Lampshaded when Diana makes him read and review a love letter she wrote " for a friend who asked for some advice", where she outright states that she "loves because she is jealous" (in that precise order). Theodoro then writes an answer to that letter in which he hints that he loves her too, and which pushes her to (sort of) confess her love, thus further encouraging him.
- Tchaikovsky's Eugene Onegin has a tragic example: Eugene hadn't returned Tatyana's affections until after she married Prince Gremin, after which he realized that he had loved her all along. They meet, and it becomes clear that she still loves him as well, but she decides to remain faithful to her husband.
- In The Merry Widow, Danilo refuses to address the question of whether he still loves his recently-widowed Old Flame Hanna, because he doesn't want it to seem that he's only interested in the money her late husband left her, but his reaction when he hears that she's engaged to marry someone else makes his real feelings clear.
- In Twelfth Night, when Orsino learns that the object of his affections, Olivia, has married his servant Cesario, Orsino loses it — and realizes that he's fallen in love with Cesario.
- 13 Sentinels: Aegis Rim Most of the main characters have one.
- Hijiyama struggles with his feelings for Okino since he's another man, but gets upset whenever the latter flirts with another guy, to the point of even punching one of them out.
- Kisaragi and Ogata both stubbornly deny their feelings for each other, but become jealous if they hear that the other was giving someone else attention.
- A non-romantic variant of this happens in Persona 4. Rise, an Idol Singer who's on hiatus, is forced to realize how much she actually used to love being an idol in part because of her jealousy over the rising popularity of her rival Kanami, who's seen as Rise's replacement.
- Super Robot Wars games play with this trope and Kouji Kabuto. Kouji in Mazinger Z has Love Interest in the form of Sayaka. Kouji also appears in UFO Robo Grendizer, where he has another Love Interest, Maria Grace. Both of them are Tsunderes. It's a Running Gag that whenever they meet in Super Robot Wars game, they both get hit by a Green-Eyed Epiphany and start fighting over him. The best part? Kouji has no idea what's going on.
- Valkyria Chronicles plays with this trope when dealing with Welkin and Alicia. Welkin's mannerisms and (for the lack of a better word) obsession with nature put Alicia off in the early going, but as the game progresses, she begins to appreciate how Welkin's knowledge gets them out of rough situations. The anime, however, jacks it up.
- Bittersweet Candy Bowl: LUCY. Oh dear god, Lucy. After nearly a decade of Belligerent Sexual Tension with Nice Guy Mike, she finally realizes she's in love with him - almost a year after he gets back together with Sandy! To add insult to injury Lucy's constant teasing has pushed Mike to the point where he wants nothing to do with her. Can you say "heartbreak?"
- Margaret from College Roomies from Hell!!! only starts to return Dave's affections when he finally starts to return Blue's.
- El Goonish Shive: Elliot and Sarah are childhood friends. Sarah isn't in denial about her feelings, but Elliot pretends he doesn't notice, and he's dating Nanase. When Sarah finds this out, she runs off crying. Who steps up to the plate and fixes things? Nanase, of course, by dumping Elliot so she can move on and he can be with Sarah. It helps that Nanase later realizes she's a lesbian and this is why she never felt sexually attracted to Elliot.
- Skin Horse: Marcie has started 'dating' Chick Magnet/Wholesome Crossdresser Tip. Slightly less effeminate Chris (who is begrudgingly forced to admit that he understands why Marcie is attracted to Tip a little too well) won in the end when his jealousy forced him to make a move for Marcie... which may have been Tip's intention all along. For the record, Tip's reaction to being dumped was essentially "K. Can we still have sex?"
- In Shadow of the Templar, Sandra's jealousy of Mike's relationship with Diana is one of the major things that lead to them becoming a couple at the end of the third book.
- Subverted in the "Burning Low" episode of Adventure Time when it is made to appear that Princess Bubblegum is jealous of Finn dating the Flame Princess, even including an overwrought "I thought I was ready for this!" after she found out. In the end, she's actually conflicted because she knows that extreme romantic feelings would stoke Flame Princess's flames to the point of destroying the planet, and she's aware that she'd consequently have to hurt Finn by forcing him to stop dating Flame Princess.
- Code Lyoko: Tired of this trope rearing its ugly head over and over again between her and Ulrich, Yumi finally decides to put a stop to it by once and for all being Just Friends. The plan has failed as marvelously as you would expect.
- In the Family Guy episode "Stuck Together, Torn Apart," Peter and Lois are advised by a marriage counselor to go on a trial separation and date other people after Lois becomes frustrated with Peter's jealousy over her having coffee with an old boyfriend. At first, Lois is supportive of the idea of a trial separation, but when she witnesses Peter on a date with Jennifer Love Hewitt it provokes her into a jealous rage. Because of that, Lois can finally understand how Peter can get so jealous, and the couple resolves to live with their mutual jealous natures.
- Kim Possible:
- Ron's jealousy towards Kim's relationship with Eric is what ultimately made him realize that he has feelings for Kim.
- The convenient Mankey/Monkey concerns Ron had about Kim's earlier boyfriend, Josh... although Ron helped her somewhat with that romantic pursuit despite his misgivings.
- The same happened to Kim herself when she jelled against Ron and Yori. And Ron's growing friendship with Felix as well, which was especially amusing since Kim apparently has a "Ron Night" each week, of which both she and her parents are aware, and yet she didn't consider that maybe they had a little more going on than simple friendship.
- In Star vs. the Forces of Evil, Star Butterfly constantly encouraged her friend Marco Diaz to ask out his crush, Jackie-Lynn Thomas. In "Bon Bon The Birthday Clown", when Marco and Jackie finally go out, Star becomes insanely jealous.
- This is directly mirrored in "Lava Lake Beach" with Marco's jealousy of seeing Star kiss Tom.