Hogwarts' nerdiest nerd failed to get an Outstanding in just one subject, and fans know why.
As each book in the Harry Potter series became more action-oriented, with students constantly battling evil wizards, it was easy to forget that J. K. Rowling used to always emphasise that Hogwarts was a school rather than a battlefield. Early on, fans got a massive kick out of reading about Harry and his friends attending various interesting classes, arguing with the teachers and conducting magic experiments.
And from the very beginning, everyone was sure who among the gang was going to be getting perfect grades in all the classes upon graduation: it simply had to be Hermione.
Thus, it came as a shock for many when Hermione got an Outstanding in every single class except one: Defence against the Dark Arts. The class taught students how to defend themselves and others against the Dark Arts, such as curses, hexes and various evil fantastic beasts. It didn't come across as incredibly challenging for Hermione, yet she only got an Exceeds Expectations and not an Outstanding in it.
Over on Reddit, fans have come up with two possible explanations for this unexpected subpar performance. For one, for some reason, Hogwarts was constantly changing the instructors for the class: over the years, Harry and Hermione studied under five different teachers in Defence against the Dark Arts. Given this crazy turnover of instructors, it's no surprise the students learned so little.
The only instructor that was actually good at what he taught was Remus Lupin, but he didn't last long in the position to impart his wisdom to his charges. So when it came time for the final exams, the students' grasp of the subject would have been patchy, at best.
Second, Defence against the Dark Arts always put practical skills above theoretical knowledge, and Hermione was never particularly good at practical magic. Whereas Harry and Ron were natural when it came to casting spells and improvising, Hermione was often straight-jacketed by her overreliance on academic knowledge.
Harry and Ron may not have been good at passing exams, but their instincts more than made up for their lack of academic ability, allowing them to carry the day when push came to shove in real-life confrontations.
So, at the end of the day, Hermione's Exceeds Expectations in Defence against the Dark Arts was, in fact, a remarkable achievement for her, given the subject's focus on practical magic rather than theoretical knowledge.