At least some of her anger towards the Half-Blood Prince

Don’t get us wrong, Sectumsempra proved to be a nasty business but Hermione disliked ‘the Prince’ long before Harry impulsively unleashed that dark little spell on Malfoy. Hermione initially distrusted the book because she thought it could be dangerous, Tom Riddle-diary style, but it turned out to just be a Potions book that gave Harry little pointers to transform him into a better student than she.

Turns out that Hermione wasn’t enjoying being the second-best student in the class for once, especially coming second to someone who was deviating from the set instructions and – let’s face it – sort of cheating. But despite all the misgivings, the Half-Blood Prince did do the trio a few favours. It won Harry the Felix Felicis that proved rather helpful later on, and it inadvertently saved Ron’s life by advising Harry to give him a bezoar.

Fair play to Hermione, however, for figuring out that the ‘Prince’ was something to do with an old Hogwarts student called Eileen Prince...