"Insufferable know it all".
This might be an upopular opinion, but after re-reading the books, I think this statement about Hermione is slightly true. Now before you jump down my throat with pitchforks, I am not completly bashing Hermione's character as she is still one of my favourites, but rarely do I ever see the fandom ever talking about this side of Hermione.
Hermione, whilst mostly a very loyal and good friend, was often petty, jealous and downright unplesant whenever she thought that someone else was right and she was wrong. Like when Harry was down in the dumps after almost killing Malfoy, instead of offering some level of empathy, or even waiting later to say something, she choose to gloat to Harry that she was right about the Half Blood Prince book. even later on when Harry was feeling misreable about Dumbledore's death, she choose to bring up her theory of the Prince book being owned by a woman, to once again gloat that she was right.
I still love Hermione's character, but she is just as flawed as Harry and Ron and I'm really confused as to why the fandom give Ron, and sometimes Harry, grief for their flaws, yet this side of Hermione is almost always left out. There are other examples of her being petty and jealous as well btw: The whole rabbit thing with Lavender in Prisoner of Azkhban, her attitude towards Ron in HBP as well.