Headcanon: Joffrey genuinely believes that he deserves to be King, and he genuinely hopes that if he ever gets the chance to take back the Iron Throne Arya will be with him. Not because he wants to see her suffer or take her hostage, but because he wants to prove that he can rule. He also figures that the fact he'll be able to crown her Queen will give him the upper hand in their relationship. Because it's still a competition and he's in it to win it.
Headcanon: Modern AU Joffrey has a terrible home life, so he hangs around at the Stark house a lot. Even though he's a complete dick and they don't think he's good enough for Arya, the Starks make an effort to include him. They might not be friendly, per se, but they include him in family arguments, family movie marathons, and the Stark kids are always inviting him to parties.
Headcanon: Modern AU Sansa is a massive One Direction fan. When she heard that they were touring she promptly bought two tickets and gave one to Theon. Robb and Jon spent weeks teasing him about it, and suggested that he should come up with some kind of excuse to get out of it. Sansa was super excited though, and Theon couldn't bring himself to disappoint her. It turned out that concert was full of screaming teenage girls, and he was the only guy, but he still wouldn't have missed it for anything.
Headcanon: Before Ned and Cat married, he felt completely inadequate. Brandon was always the more sociable of the brothers, and he thought that his wife would end up loving a memory more than she did him. As a result he wrote her lots of terrible poetry, though he never managed ro finish and threw all of the papers away. At least, he thought he did. Cat found them, and wrought they were all completely awful she kept them anyways. She still teases Ned about it now.
Headcanon: Joffrey and Arya, in a modern AU, try to rebel as often as possible. Most of the time they skip classes to smoke behind the bike shed, but other times they go partying, or urban exploring. Joffrey may be a dick, but he makes sure that he keeps an eye in Arya at all times. Other times, it's Arya who has to keep an eye on him. They may not always agree, but no one else is allowed to pick or tease.
Headcanon: Modern AU exchange student Dany always felt out of place at Westeros High. The other students already had their cliques and designated friendship groups and she was left well and truly alone. Well, until Drogo the history teacher caught her eye. Technically their relationship is wrong, but Dany doesn't take kindly to being told what to do, and it was Drogo who managed to make her new school a home.
Headcanon: (Our RP) Sansa feels an immense amount of pressure to live up to other people's expectations. Sometimes she feels as though hushed needs to be like Cersei, and other times she feels as though she needs to be like Arya or her mother. The only person who she feels completely comfortable around is Theon, because he understands what it's like to feel as though you need to fit a particular image. One night she has a little much to drink and it all comes flooding out. Neither of them need to say anything more, because sometimes hugs speak a whole lot louder than words.
Headcanon: Cersei always told him that women should dress well and take care of their appearance. He's used to the glittering jewels and extravagant gowns of King's Landing, but Joffrey never thought of such finery as being truly beautiful. It couldn't make up for a watery personality, or for weak wills and a slow tongue. It never made his mother any kinder. That's why he prefers the Arya that he sees when he stumbles upon the Hound after the riot in King's Landing. The Arya with matted hair and dirty clothes. He'd never admit it, but he's frightened that if she begins to dress like a proper lady she'll turn into another Cersei. Joff doesn't want to lose the one person who's always been completely honest with him, no matter how much he hates her.
Headcanon: Modern AU. Ned sucks when it comes to Valentines day, but his kid's are always ready with wacky suggestions and crazy schemes. At first he stares at them in astonishment, and then he tells them that he definitely isn't going to go along with any of their plans, but somehow he always ends up doing what they tell him. Cat seems to know, but she doesn't seem to mind either.
Headcanon: Modern AU. Sansa always felt really intimidated by Theon's older sister. Everytime she visited the Geyjoys, Yara would grill her on her relationship with Theon. Most of the older girl's questions were completely inappropriate, and extremely personal, and Sansa would be left stuttering and stammering. But in between the comments regarding their make-out sessions, and whether they'd 'done it', Yara offered her pieces of advice. They were small, hardly noticeable in hindsight, but it was nice to know that someone was looking out for them.
Headcanon: Dany was always impressed by how strong Drogo was. It inspired her, and it made her want to grow stronger as well. As Khaleesi she felt she owed it to her people, to the people who followed Drogo and who believed in him. Drogo, in turn, was impressed by his wife's strength. They grew to love one another, and they grew to learn from one another. Individually they were powerful, but together they became undefeatable.
Headcanon: Joffrey and Arya never marry. Marrying is a convention, the sort of thing which society expects, and neither of them fit the mould of what they 'should be'. They've become their own people, independent of their parents wishes and expectations. Sometimes it's difficult, of course, but they have one another. Underneath the banter and the petty insults lies something reassuring, something comforting. Joffrey and Arya won't change for other people, only for themselves and for each other.
Headcanon: Modern AU. Sansa spends a year planning their wedding. With Cat's help she selects the right coloured tablecloths, writes out the guest list, designs the invitations, and nuts out every last detail. On their wedding day, however, she balks. No one finds out that she's missing until it comes time for Ned to walk his daughter down the aisle. Sansa Stark is nowhere to be found, and Theon is left to stand alone at the altar. He finds her eventually, locked in the female restrooms and sobbing hysterically. They've spent thousands on the wedding, and it takes half an hour for Sansa to admit that she wants something smaller. Theon, it turns out, doesn't give a damn about how large or small the celebration is. He just wants Sansa to smile again. And, to his relief, she does.
Headcanon within a headcanon: Dancing is a way to make money, but it's also a passion. There's a fire in her eyes which flares when she's performing, and not once does she struggle to find a smile. Unfortunately the cash doesn't always flow so easily, and she finds herself living with the bare necessities. That's when he swoops in, with his money and his promises. But Dany doesn't want anyone to take care of her, she wants to fly, and though he offers many things -big houses and luxurious furs- he can't offer her freedom. It's only when she marries Jorah, so slow and stubborn, that she realizes how blind she'd been. Freedom, Dany learns in time, is not always so obvious. She's left with no fire, only cinders.
Headcanon: Modern AU. Margaery Tyrell is known for her parties. They're wild. They're out of control. And they're impossibly cool. Sansa begs with her parents for permission to go, and when they finally agree she rings Theon up immediately, barely able to string a coherent sentence together. Unfortunately the Tyrell party doesn't quite live up to her expectations. She dances for a while, loses track of her boyfriend, and has too much to drink. Within several hours Sansa Stark has passed out on the couch. It takes Theon half an hour to find her, and by the time he does he's a little tipsy himself. Neither of them remembers exactly how it happens, but they wake up the next morning, curled together on the couch. It's the only aspect of the party which Sansa doesn't find disappointing.
Headcanon: She taught him to fight. No to swing his sword about as though he knew what he was doing, but to actually fight. After being taken by Petyr it was the least she could to make sure that she had a capable companion. There were thieves and rogues on the road, and Joffrey was no match for them. At first he was no match for her, but over the next few months he began to improve, until eventually he could hold his own. She never got tired of whacking him though, even if the whacks themselves were a lot gentler.
Headcanon: Cat is the only person who ever sees Ned cry. He can't cry in front of his men, his friends, or his children. But sometimes, when the burden of protecting Winterfell becomes to much, he allows Cat to see his tears. The nightmares of what happened to Brandon, his father, and to Lyanna still haunt him, but only his wife sees the true extent of his pain. Somehow, he thinks she might even understand.
Headcanon: Modern AU. The first thing that Sansa and Theon did when they moved into their own place was adopt an abandoned Husky from the nearby animal shelter. The dog was terrible when it came to taking commands, and she was a terror to walk. Several times she shredded holes in the couch, and she was constantly jumping onto their bed. At Sansa's insistence they named her 'Lady' anyways, and she got along fabulously with Arya's German Shephard, Nymeria.
Headcanon: It took ages for Dany's dragons to warm up to Drogo, they were suspicious of him and developed a terrible habit for interrupting intimate moments. Drogo, in turn, was suspicious of them. They wre magnificent beasts though, and capable of protecting Dany from almost anyone, so he sucked it up. Over time the dragons grew on him, and they learned to trust one another. He hasn't yet learnt how to fly, but he's getting there.
Headcanon: Modern AU. Ned always had a massive crush on Cat while they were at High School. Unfortunately whenever he spoke to her he found himself fumbling for words, or restricted to subjects such as homework and study. He resolved to change this by joining the swim team, figuring that he's be able to grow closer to his crush. Unfortunately his first training session didn't go as planned. Ned woke up beside the pool, Cat and the lifeguard standing over him. A week later the pair starting dating, and they still laugh about it now.
Headcanon: When Sansa was little, maybe around four or five, she would spend all of her spare time making flower crowns for her older brothers and their friends. Robb and Jon never wanted to wear theirs, embarrassed by how girlySansa's presents were. Theon, Robb's best friend, was the only one who would wear his for more than ten minutes. As she grew older, Sansa slowly stopped making crowns. She didn't, however, stop spending time with Theon.
Headcanon: Modern AU. Westeros High holds an annual dance, one to which all students are invited. Joffrey doesn't know how to go about asking Arya, and he doesn't want to give her an opportunity to catch him out, so he dares her to go with him instead. She accepts, and they spend most of the night telling themselves that it 'definitely isn't a date'. Instead they talk about how stupid Arya's siblings are, how immature it would be to spend all night dancing, and how terrible the punch is. Needless to say, they end up dancing anyway. But it definitely isn't a date, just another dare.
Headcanon within a headcanon: Petyr has always been visiting the Starks, ever since they were little. One day Sansa discovers a couple of old boxes in the attic, and she convinces Theon to help her go through them. There are plenty of pictures of Ned and Cat. Ned and Cat at swimming meets, Ned and Cat at prom, Ned and Cat getting married. Petyr is in a fair few of them too, though he lurks in the background. For a couple of days Sansa feels bad for kicking him, but then she remembers the expression on his face when he spoke to her and decides that he deserved it.
Headcanon: Modern AU. Dany has a part-time job at a cafe, and that's where she and Drogo first meet. He comes in every morning for a coffee, and smiles at her from across the counter. Dany prides herself on being able to figure out her customers, but she can never quite figure out Drogo. She, on the other hand, fascinates him and a month or two of not speaking to one another he asks her if she'd like to go to dinner with him. Dany agrees, and from there on in the pair are insuperable.