Plot Bunnies
She is already head-over-heels for him even when Team 7 has barely formed.
They're on that rooftop, with everyone introducing themselves, but she doesn't hear anything. How can she concentrate on anything, when Sasuke is distracting so much by just being…Sasuke? Anyone who questions her can just go screw themselves and die, because to her, it makes perfect sense.
Sakura looks at Sasuke, and she can't help but admire his eyes, so obsidian and mysterious, his lips, perfectly proportioned, his face, infuriatingly calm, and his sitting posture, so straight and proud. She notices everything about him. Every little thing. And that's why she doesn't miss it when that trace of hatred and detestation flashes in his eyes when he talks about surpassing his older brother and making his father proud.
Kakashi-sensei and Naruto are blind to it. They don't stalk Sasuke as she does. They only see the jealousy, and nothing more.
At that moment, Sakura vows silently to aid Sasuke any way she can.
It's during the chunin exams when she realizes her worthlessness.
Naruto and Sasuke fight against some enemy genins with grace she can only hope for, and as she watches from the sideline, a spark of bitterness roots insider her heart. She has the potential to be a good ninja, she knows. She is the one with the perfect chakra control. She is the most intelligent in her academy class, except for maybe Shikamaru. She is the only girl in her year to have come from not a prestigious clan and still manages to become a genin.
It isn't her fault that her teammates are the Hokage's obnoxious son and the younger son of the head of the Uchiha clan. It isn't her fault that Naruto's so likable and good-natured, or that Sasuke is considered talented even among the Uchihas. It definitely isn't her damn fault that Naruto's father is Kakashi-sensei's former sensei, and that Kakashi finds his younger self reflected in Sasuke.
Despite everything, Sakura's done her best. Everyone keeps comparing her to her damn teammates, and doesn't it ever occur to them that anyone who has the misfortune of being on the same team of Naruto and Sasuke will look weak in comparison? Kakashi lavishes all his time and attention on them, making sure that those two grows into legendary shinobis, while poor, poor Sakura is left behind.
Observing the battle from her hiding spot, Sakura pushes aside the feelings of bitterness. Instead, she watches Naruto and Sasuke as they dance across the clearing, kunais and weapons flying overhead. Both of them has their own unique fighting style, and Sakura commits their movements to her memory.
A few months after their chunin exams (which none of the Konoha teams passed, not even Shikamaru), Jiraiya takes on Naruto to travel and train, while Sasuke seeks out Orochimaru (who, mind you, is not a missing Nin) to further enhance his skills. Team 7 is scattered, and Kakashi disappears to god-knows-where. Later, Sakura hears that Ino has requested for Tsunade to take her as an apprentice, and Tsunade has agreed. So, since Ino is unavailable during her apprenticeship under the legendary healer, Sakura is conveniently placed on Team 10.
But Sakura doesn't consider herself to be part of the team. She works together with Shikamaru and Choji as required, and dutifully follows Asuma-sensei's orders, but she makes no effort to extend her friendship to them. To Sakura, the members of Team 10 are just acquaintances, nothing more. On her stay with their team, Sakura does what she does best: she observes. She notices the way Shikamaru's eyes always give away which direction he's going to attack from, the way Choji touches his right wrist lightly whenever he's hiding something, and the way Asuma-sensei's hand twitches as he prepares to attack.
She detects their weakness and strength, and files it all away in her brain for future references.
Sakura discovers a new pastime after the first year Sasuke and Naruto left.
Stalking fellow shinobis.
Her new hobby is about as freakish as hobbies can get, but screw what people think, Sakura is doing her own thing. It's not like anyone notices her either. She has followed Leaf shinobis she doesn't even know of, but she always remembers their faces and memorizes everything little habits she sees from her observations. Sakura has gotten so used to observing/stalking people that it doesn't take her any more than half a day to discover everything there's to know about someone.
Sakura's officially a stalker of the first order.
Currently, she's a chunin, and she's damn good at masking her chakra, so nobody ever senses her. She can testify to this claim on her abilities because she stalks the Itachi Uchiha.
Even if she resents Sasuke for his inborn talent, she can never forget the vow she took when they were genin. She vowed to aid him in whatever way she can to surpass his older brother, Itachi. Now that Sasuke and Naruto are gone, and she has nothing better to do in her free time, she has taken it upon herself to stick to the Uchiha heir like a shadow.
She finds out that he loves to eat dango. He trains like a maniac, and he seems to have a certain distaste for anything spicy or bitter. His dominant hand, his right, tenses whenever he gets uncomfortable, and his left hand clenches whenever he's angry or annoyed. Sakura can't be certain, but she's almost positive that he has more fangirls than Sasuke, which is to say quite a feat. The Uchiha heir also seems to enjoy helping people, carrying old ladies' heavy bags for them, comforting crying children, etc.
And that's when Sakura first starts to doubt what the hell Sasuke's problem is. Itachi seems calm and patient enough, and even though he is arrogant like all Uchihas (you can't be an Uchiha and not be full of pride), he does not flaunt his skill or superiority in front of others.
All in all, Itachi is as decent as Uchiha men can get, and Sakura can't help but wonder what went wrong between Sasuke and Itachi that led Sasuke to hold so much hatred for his brother. Still, it is not her place to question anything, so she keeps her mouth shut – for now.