Why not Asuka? The big question - pretty obvious answers. What? Asuka and Shinji hate each other, then they love each other? No way. Alright, this would actually work in a normal relationship IF the two had common personalities. However, Asuka is a loudmouth and needs to have all attention on her in order for her to be recognized. Most people say that she does that because that's the only way she can keep her sanity. But, that's her personality, and her personality nontheless. Shinji's personality, however, is an introverted boy, who doesn't like being around others and doesn't talk much. The antithesis of Asuka's personality, but related to Rei's.
Shinji is Asuka's personal punching bag. I find it obvious he isn't going to like her, but some of you need to get your heads checked. I feel Asuka belongs with someone who can fight back, and even sometimes, defeat her at her own game (Touji actually comes close, but i'm not going to start) And let's not forget, their "popularity levels". Shinji is pretty much lame and boring to most people, while Asuka is one of the more popular people. They're from two different "socioties". However, Rei is on the same level as Shinji. This, and because they're both introverted, is why they can talk so much easier.
And though it seems that Shinji does care about Asuka, he probably does in a friendly way. How do I know? Simple. He "tries" to help out Asuka at times. However, has he ever helped her when she goes through her "inferiority complex phases"? I don't think so.
And here are some reasons from the show:
Shinji-Asuka Fan: In Episode 8, Shinji looks at Asuka while she's getting into her plug suit. That's sexual tentsion right there.
Reply: He heard a bunch of rustling sounds, of course he's going to look! He had to check. And plus, when he looked, he didn't look too amused.
Shinji-Asuka Fan: Shinji decided to go with Asuka during her first sortie.
Reply: Rephrase that. Asuka dragged Shinji along with her into her Eva. Plus, Asuka said she was giving him a first hand look at her piloting skills. This scene is really a foreshadowing of things to come, which is that Asuka and Shinji will end up not getting along. Plus, this the first of many times that she's a show off. And don't tell me she's not a show off, because Asuka is overly-competitive and has an inferiority complex.
Shinji-Asuka Fan: Shinji and Asuka were about to kiss in Episode 9.
Reply: Shinji is searching for affection everywhere, blindly. This girl was thrown at him, so of course he'd react that way. Plus, if he was able to kiss her, Shinji would probably feel as if he'd gain her respect. And it is possible that he had feelings for her in the beginning, but I fell he lost interest after this episode.
Shinji-Asuka Fan: Shinji rescues Asuka as she falls into the volcano.
Reply: And you would let her die? Okay, I know Shinji jumped in Eva-01 for Rei, but that was different. He was putting his own life on the line. He was afraid for his own life. But he risked himself for her. In this situation, he goes magma diving for Asuka, but he's already a seasoned pilot and knows that Unit 01 can withstand alot of damage, he really isn't as in much danger as he was in the first episode.
Shinji-Asuka Fan: Shinji looks up Asuka's dress in Episode 11 while they were going up the vents.
Reply: Christ, he had to see where he was going! He's just trying to reach his Eva and complete his mission. And if he didn't look, and was climbing too fast, his head could have probably gone somewhere it shouldn't, and then he'd be in real trouble.
Shinji-Asuka Fan: Also in Episode 15, Asuka and Shinji kissed.
Reply: (Borrowed from Ryan Xavier) They were bored, especially Asuka. Plus, Asuka's been watching Shinji stare at Rei all day. Her roommate hasn't payed any attention to her at all. So, this "i'm bored kiss" was her last resort.
Shinji-Asuka Fan: Asuka compliments Shinji on "being the best" in Episode 16.
Reply: She was being sarcastic. She feels violated every time she hears how much higher his synch is than hers. Though she talks sarcastically most of the time, she was especailly sarcastic here. Again, inferiority complex.
Shinji-Asuka Fan: Asuka waits with Misato after Shinji comes out of the 12th Angel.
Reply: Yes, that is pretty convincing. However, she asked Misato if Shinji's going to be punished. She wants to see Shinji get "what's coming to him" from his surrogate mother. And knowing Asuka, she's probably going to add to it by insulting him.
Shinji-Asuka Fan: In Episode 17, Touji makes a "husband-wife" comment.
Reply: This is one of Touji's pranks, more character development.
Shinji-Asuka Fan: Shinji is in a staring at Asuka while she's with her step-mother.
Reply: He envies her, as if she were a big sister. She has a mother figure, and he never had one.
Shinji-Asuka Fan: Shinji tries to talk to Asuka after the fifteenth Angel.
Reply: Shinji's character is one that is compassionate and caring. Of course he's going to check on her. Plus, in a usual anime show, this would be a scene where the character expressed their love. However, Shinji doesn't do that. He still treats her like a friend, though she thinks of him as an idiot.
Shinji-Asuka Fan: Throughout the End of Evangelion movie, Shinji calls for Asuka's help.
Reply: Shinji no longer has the confidence to talk with Rei in his current condition, and he's afraid of Misato because of her cold remarks. Asuka is his last hope of someone to actually talk to.
Shinji-Asuka Fan: Shinji masturbated over Asuka. This also shows he's growing up into a man which Asuka needs.
Reply: If you think that scene meant love, you need to have your brain examined. Would you like for this to happen to you?! Masturbating over you're naked body?! He shows no respect for her. I also see this as a foreshadowing of the two rejecting each other, because in my opinion, Shinji rejects Asuka at the end of EoE. And okay, Shinji has hit rockbottom here, and is taking advantage of the situation, but still, it's no respect whatsoever.
Shinji-Asuka Fan: Shinji and Asuka become the new Adam and Eve.
Reply: (Buzzer) Go watch the movie again. Shinji rejects Third Impact, so mankind will go back to their original forms. This is an alternate reality we see at the end of EoE. And in my opinion, the TV and movie Endings are synchronized. The TV Ending is what's going on in the mental World and the movie Ending is what's going on in the physical World. The whole point of Evangelion was that Shinji wouldn't need to be praised/congratulated for his deeds like before. When everyone congratulates Shinji in the TV Ending, can be happening the same time Asuka and Shinji lie on the beach. If this is so, Asuka is a "congratulatory gift", which Shinji is rejecting because he no longer needs congratulations.
Shinji-Asuka Fan: Though Shinji seems interested in Rei during the beginning of Evangelion, he gets more interested in Asuka later in the series.
Reply: They live in the same apartment stupid, of course there would be a lot of scenes with them together.
Shinji-Asuka Fan: Asuka is a very outgoing person, and may help Shinji escape his introvertedness.
Reply: Obviously, you're not an introverted person. (I am) Introverted people are attracted and drawn to other introverted people. (I should know) Introverted people, well, I don't want to use the word "fear", but, we sort of drive outgoing people away. Outgoing people sometimes just make introverted people more introverted. And even though Shinji's "introverted barrier" breaks down throughout the show, the times it breaks down the most is when he loses someone. (Example: Losing Rei psychologically, Losing Kaworu physically, Touji and Kensuke moving out.) That's all just preperation for the final episodes, where he truly has hit rockbottom, and is begging for help.
Shinji-Asuka Fan: 99.9% of the time, Shinji and Asuka argue, a sign of affection.
Reply: Asuka needs to argue to keep her sanity, and has become a person who loved to argue. She does nothing but argue, not only with Shinji, but with Touji and Kensuke, too. And though it is a psychological fact that opposites usually attract, and this is a show based on psychology, it's completely evident that they don't get along.