You never know what you've got until it's gone. There are some people that we hate, feel indifference for, or just don't feel like being around. But we're stuck with them, so we muddle through and put up with them because there's nothing we can do about it. Then, that person is suddenly out of our lives. Great, right? Wrong.
For some reason, you take their absence a lot harder than you expected to. It's not until they're gone that you start to like them. Maybe you've become so used their little quirks you can't imagine your life without them. Or maybe you realize that they're the best thing to ever happen to you. Whatever the case, you realize too late that you actually love them.
It doesn't necessarily have to be romantic, in which case it may involve The Not-Love Interest. It can be that annoying kid down the block that you unintentionally grew fond of or a relative you never appreciated. Though, it could also be an ex-lover that you fell back in love with, or a friend you never saw in a romantic light. Sometimes, you learn a little too late that the person you miss was better than you initially believed them to be.
A strong risk of separation is sometimes enough to invoke this trope. Then whoever has fallen in love will do anything to stay with the object of their affection. Reunions are possible, but not always.
Subtrope of Love Epiphany. Oblivious to Love characters may be prone to this. Compare Can't Live With Them, Can't Live Without Them and We Want Our Jerk Back. Contrast Absence Makes the Heart Go Yonder.
Note: This is not the same as losing someone you already loved.
- In Beyond the Boundary, Akihito realizes he's in love with Mirai after Mirai had already sacrificed herself to the Beyond the Boundary and wiped herself from existence in order to save him.
- In Freezing, we have a familial example in Kazuha Aoi. Because of her strong connection to an otherworldly presence, she found herself detached from other humans who didn't have a stigmatic body, including her mother. This led to a tragic event where she killed her mother, only to start crying after her spirit visits her a final time to say good-bye and not blame herself. She later notes that she could only truly understand what her mother went through after raising her brother.
- In I Wish, Seven doesn't notice he's fallen in love with his master until he dies, at which point Seven's heart breaks.
- In Mobile Suit Gundam SEED, Flay and Kira share a very unhealthy relationship wherein she basically tries to manipulate him onto a path of self-destruction (blaming him for her father's death), but it's not until Kira is seemingly killed by Athrun that Flay realizes she has fallen for him for real in the meantime. That particular subplot doesn't end well at all.
- In Tokyo Ghoul, this happens on several occasions.
- Tsukiyama spends months working with Kaneki, attempting to earn his trust so that he can eventually eat him. It's only after Kaneki is seemingly killed in battle that Tsukiyama is forced to realize he had come to genuinely care. Unable to cope with the loss, he spends the next two years in an Angst Coma and only finds the will to live when shown evidence of Kaneki's survival. He admits that he was happiest during the time he spent with Kaneki, and desperately tries to reclaim that lost time. But when confronted with Sasaki's conflicted feelings over his past, Tsukiyama realizes he can't bear to take away the other man's current happiness.
- After keeping others at arm's length throughout the series, Akira Mado loses both Amon and Takizawa in a single night. When confronted over her stoic attitude about the loss, she breaks down into tears and admits that she loved them both. Nearly three years later, she is forced to confront Takizawa after his transformation into a Half-Human Hybrid. At first, she takes part in the failed attempt at Staking the Loved One.....but ends up Taking the Bullet to protect him. Wounded, she admits that she can't stand the thought of losing him again.
- Related to the above, Takizawa experiences this with Akira more than once during the series. In the original series, he comes to realize his feelings for his former rival just before seemingly dying in battle. Come the sequel, he initially tries to kill her for "betraying" him, but comes to his senses after she's wounded protecting him. He ends up switching sides, and remains at her side during her treatment.
- In Runaways, Nico begins to realize that she has feelings for Karolina after the latter has gone off to space to fulfill an arranged marriage. Adding to her turmoil, Karolina's intended has cut off all communication with the Runaways, leaving Nico to wonder if Karolina is even still alive.
- In Bastard!! Gil Alien realizes how much his family (and most of all not his mother, but his stepfather and stepsiblings) means to him after he gets thrown into the past with hardly a hope of return.
- In One-Punch Man NSFW fanfic Mirror Mirror the alternate timeline Saitama thought Genos was annoying and clingy but otherwise saw him as a good friend. It isn't until Genos died that he realized that his feeling ran much deeper and spends the next five years mourning and rising through the ranks in Genos' memory.
- Gone with the Wind: Scarlett doesn't see that Melanie was her closest and truest friend until Melanie is on her deathbed. Nor does she realize that she loves Rhett much more than she loves Ashley until Rhett decides to leave her.
- Pixel Perfect: Roscoe falls in love with Samantha not long after she kisses him.
- In the Arcia Chronicles, Nanniel is a staunch proponent of Elven supremacy, permanently in opposition to her husband Asten and his brother Emzar's more pro-human stance. After Asten is killed by Nanniel's faction and Emzar decides that he had enough and leaves the hidden Elven kingdom with his supporters to live with the humans, Nanniel realizes that despite their differences, she has actually been in love with Emzar for thousands of years and decides to follow him. Ironically, she dies saving a bunch of human victims of a Roigian cult because that's what Emzar would do, but neither he, nor anyone else ever learns about her change of heart.
- In most versions of Beauty and the Beast, this is the purpose of the Beast's Disney Death. Until that point, Beauty sees him as a friend but still can't look past his appearance (and in some versions is all too infatuated with a prince from her dreams actually the Beast's true form), but nearly losing him makes her finally realize that she loves him.
- Bridge to Terabithia: Jesse has a crush on his teacher Ms. Edmunds and doesn't realize how much Leslie means to him until she dies.
- In The Difficult Child, a short story by Kir Bulychev, the protagonist at first can't stand her adopted brother a vindictive prankster bat-like alien. Then they both grow out of it a little as she gets used to him and he becomes a bit more sociable, one time he saves her life, but still the relationship remains extremely strained. Only after the home planet of his species is found and he has to leave Earth forever they realize how strong their sibling bond was.
- Harry Potter spends most of the book series despising his potions professor, Severus Snape, who treats him and his friends harshly both in and out of class. It's not until the end of the final book, after learning that Snape had secretly been working to protect him and bring down Voldemort all along that Harry comes to respect and admire Snape, and names one of his sons after Snape. However, by then, Snape had already been killed by Voldemort.
- Hollow Kingdom Trilogy: As a (mostly) human woman living in the goblin kingdom, Emily has to marry a goblin. After being turned down by her (because she was distracted by the kids she was babysitting, and because he didn't flat out say "will you marry me"), Seylin sets out to find his elf roots, because he looks exactly like an elf himself although he's a goblin. Emily is offended by this (partly because she is told that he went to find an elf bride) and claims to want to journey to find her human nature, but really to chase after him.
In her mind, she practiced the speech she would say when they met. It had changed over the course of the last few weeks. "Get married? I don't really want to marry anybody, but if I have to, I'll marry you." "Get married? If you feel that way, it's all right with me." "Get married? I'd like to— if it's with you, I mean." And now, "Where are you, for heaven's sake? Why aren't you looking for me? Seylin, don't you want to get married?"
- In The Hunger Games Katniss insists that she isn't in love with anyone and is mostly just confused about how she feels for Peeta and Gale. That is, until the antagonists imprison Peeta and hijack him, essentially brainwashing him into hating Katniss and wanting her dead. While the book never explicitly states the exact moment when she realizes her feelings the reader can take a guess at any moment from her stating that the loss of him has taken away her will to live to her telling him how she feels.
- In Pride and Prejudice Elizabeth didn't start to fall in love with Darcy until after she had already rejected his marriage proposal, soon after which they had parted on bad terms.
- In A Song of Ice and Fire Sansa Stark is the least close to her illegitimate brother Jon Snow of her four brothers (Robb, Jon, Bran and Rickon) — albeit, all of them love her and she does love them — but once she's surrounded by enemies with most of her family dead or missing with Jon hundreds of miles away on the Wall, it's then that she realizes how much she misses Jon and longs to see him again.
- Stannis had very strained relationships with his two brothers, Robert and Renly. It's only after they both die that Stannis realizes how much they meant to him.
- Sylva of The Summoner Trilogy seems perfectly happy to be Just Friends with Fletcher, despite their hinted mutual attraction, up until he comes within a hair of being assassinated. The events leaves her whispering a series of Little "No's" and cradling him as he bleeds out; when he ends up surviving she apparently realizes her feelings for him are definitely not platonic, as she lightly kisses him after.
- Played with in Doctor Who. When the Doctor first met River Song, she was just another archaeologist to him, but then he learned that she was from his future. After she dies in the library, he spends the next few seasons falling in love with someone he has already lost/is going to lose. Further played with in the Series 9 finale when, after Clara is killed. The climax of "Heaven Sent" built around this.
- Game of Thrones features an extremely tragic parent/child examples in the fifth season. Selyse Baratheon abused and neglected her daughter Shireen for "being sinful", eventually giving her consent to let Lady Melisandre burn her alive as a Human Sacrifice to the Lord of Light. As the sacrifice gets underway, however, Selyse's motherly instincts kick in and she realizes that she can't bear to lose her. Selyse's attempt to save her child fails and she's forced to watch Shireen burn to death. Shortly afterwards, she commits suicide out of grief and guilt.
- Orphan Black: Vic treated his ex-girlfriend Sarah like crap but he's devastated when he thinks that she committed suicide (presumably because of him).
- Scrubs: J.D. was once in a relationship with Elliot, but they became Just Friends after breaking up. He's supportive when she becomes engaged to new intern Keith, but it isn't until the ceremony officiates the whole thing that he realizes that he did want to marry her himself.
- Torchwood: As Owen is dying Tosh tells him she loves him. After he's dead (but not gone), she tries to talk to him about it but he interrupts her.
Tosh: Well, when I told you I ...Owen: Yeah, you didn't mean it. I know.Tosh: You do?Owen: Yes, uh ... I mean, you didn't say anything before, and then, suddenly I'm dying, and it's like, "I love you." That's not love, Tosh. That's grief. You're losing something, so suddenly you desperately desire it, textbook response.
- The song "Let Her Go" by Passenger has this theme.
Well you only need the light when it's burning lowOnly miss the sun when it starts to snowOnly know you love her when you let her go
- The song "Big Yellow Taxi" by Joni Mitchell (covered by The Neighborhood and Counting Crows, and others) has this theme. From the Counting Crows version:
I heard the screen door slamAnd a big yellow taxiTook my girl awayNow, don't it always seem to goThat you don't know what you've gotTil its gone
- Cinderella released a song called "Don't Know What You Got Till It's Gone"
- Peanuts: Lucy has a crush on Schroeder, who usually acts annoyed about it and ignores her to focus on his piano. Then Linus and Lucy move away because their father got a job in another place. At the end of one strip, Schroeder remembers Lucy leaning on his piano imagining the two of them being married, and he laments that he never even said goodbye to her. Things go back to normal after Lucy returns.
- Zidane from Final Fantasy IX only realizes that he loves Garnet after she is crowned queen (and thus becomes unaccessible for him). Before that, he's all playful and flirting but doesn't think it's for real.
- Avatar: The Last Airbender:
- Zuko rebels against his uncle Iroh for most of the series, but in season 3, when they're separated because Zuko betrayed him, Zuko regrets not being more grateful and loving toward him.
- Similarly, Toph was happy to run away from her parents, but later regrets hurting them, even if they were incredibly repressive and overprotective. She has Katara write them a note apologizing.
- A darker version of this tropes occurs with Azula, Mai and Ty Lee. Azula sees people as tools or obstacles and doesn't believe in trust or friendship. However, when her friends betray her, Azula couldn't admit to herself that she really cared about them and felt hurt by their betrayal. This really takes its toll on her already fragile psyche and helps fuel her psychological breakdown.
- The Legend of Korra:
- Mako only realizes he's more in love with Korra than he is with Asami once Korra has been kidnapped by the Equalists.
- In the Turf Wars comic continuation, it's explained that this also applies to Korra and Asami. Korra realized how she felt about Asami after the poisoning, but wasn't in a state to process it. Asami realized how she felt during Korra's three-year absence, which she describes as the longest years of her life.
- In the Superman: The Animated Series episode "Brave New Metropolis", Lois encounters a horrifying alternate Metropolis in which Superman went Knight Templar following her counterpart's death. This Superman explains that he wasn't aware he felt that way about her until after she died.