Ok so Harry/Hermione isn’t impossible. Why? Because Harry and Hermione are both straight and are obviously reasonably attracted enough to each other to be such good friends. They’ve both also been through a lot of trauma, and emotional episodes together, have saved each others’ lives and have a lot in common. So no, when people say they are impossible, that’s wrong. But I do think however, Harry/Hermione shouldn’t happen and am very grateful that Ron/Hermione happened. First of all, Harry and Hermione see each other as family, as siblings. That primary sexual attraction does not exist. They are best friends. I think it is so hard for people to wrap their heads around this fact these days. With the current tv shows, film and literature we always pick up on a boy and girl’s best friendship as something more. Heck we pick up any 2 people, whether they are gay or straight or whatever as having something more because of little fact that you believe makes them perfect together. It’s easy to do this for Harry and Hermione. I don’t know if its because some of these people don’t have enough guy friends that are genuinely just good guy friends or because of how media tells us that there is always an ulterior motive there. But Harry and Hermione aren’t sexually attracted to each other in that way in the same way you aren’t to your brother, sister, cousin or whomever. Second of all, Hermione is attracted to Ron. And don’t ask why. Sometimes attraction or love doesn’t make sense and it never has to. Harry is attracted to Ginny. Therefore, it is clear that is why Harry and Hermione are not possible. Not impossible because if JKR had written it that way where they both saw something more romantic in their friendship, and pursued it, they might’ve worked out. However, they are not possible because some people, no matter “how compatible” or “how realistic” they are or “how much chemistry they have”, it doesn’t matter. When they don’t see each other that way, it’s not going to happen.