Hermione Granger is smart, capable, and caring. She keeps her cool in dangerous situations, and is always there to help you finish that last scroll for History of Magic. Hermione quickly became many readers' favorite character from the Harry Potter books – and who does she end up with? Ronald Bilius Weasley.
Really, J. K. Rowling? You're going to have this frizzy-haired angel end up with the series' comic relief? At least have her settle for the franchise's title character. Plenty of fans think Rowling did Hermione dirty by having her end up with Ron, and that opinion goes way beyond just shipping Harry and Hermione. More insane fan theories ship Harry and Draco Malfoy than Ron and Hermione, for goodness' sake. And who's even checking for Harry's canon significant other, Ginny Weasley?
It's clear that Hermione and Ron were a huge mistake. Even Rowling revealed she thinks she messed up her romantic pairings. From their compatible personalities to their undeniable chemistry, check out all the reasons why Harry Potter and Hermione Granger should have ended up together.
Hermione teaches Harry how to perfect the summoning charm before he enters the first round of the Triwizard Tournament in Harry Potter and the Goblet of Fire. And he's receptive and grateful! Compare that to Ron mimicking Hermione's pronunciation of "wingardium leviosa" in the first book and movie. Ron is reluctant to learn, and he gets defensive when Hermione tries to help.
Harry is all for learning from Hermione, and he clearly respects her intelligence instead of feeling threatened by it.
Ron's jealousy and mood swings lead to some animosity-peppered conversations with both Harry and Hermione. He's jealous of their friendship and he's jealous of them as individuals. His resentment of Harry's status as the Chosen One manifests itself frequently, and he tends to rankle at Hermione's intelligence.
Harry and Hermione, on the other hand, rarely get up in each other's faces, and they seem to have a fairly easy-breezy friendship. Sure, some would argue that Ron and Hermione's bickering would make for a more passionate coupling, but it could also lead to all-out hatred. Rowling even said she thinks Ron and Hermione would definitely be in "relationship counseling."
When Ron's underlying jealousy is worsened by the Horcrux in Harry Potter and the Deathly Hallows, he abandons Harry, claiming their mission to weaken Voldemort is fruitless. Hermione declines to go with him, opting to stay with Harry because she has faith in their cause and in Harry.
If she was all in on Ron, she wouldn't want him wandering off into the woods on his own. Sure, Ron comes back, but Hermione was there by Harry's side the whole time.
That's right – J. K. Rowling regrets pairing Hermione with Ron. Rowling talked to Emma Watson (Hermione herself) about how, looking back at the coupled-up Hermione and Ron, she couldn't help but wish she'd had Harry and Hermione end up together. Rowling said she "wrote the Hermione/Ron relationship as a form of wish fulfillment":
"For reasons that have very little to do with literature and far more to do with me clinging to the plot as I first imagined it, Hermione ended up with Ron... I know, I’m sorry. I can hear the rage and fury it might cause some fans, but if I’m absolutely honest, distance has given me perspective on that. It was a choice I made for very personal reasons, not for reasons of credibility. Am I breaking people’s hearts by saying this? I hope not."
Watson seemed to agree with Rowling's assessment of Ron and Hermione's incompatibility, saying, "I think there are fans out there who know that too, and who wonder whether Ron would have really been able to make her happy."