Harry Potter: 10 Worst Things Hermione Has Ever Done

But the bird attack was just the start of Hermione’s vendetta. Determined to annoy Ron as much as possible, Hermione starts going out with Cormac McLaggen, a large seventh-year student who tried (and failed) to become a member of the Gryffindor Quidditch team.

Dating someone purely for the sake of revenge is bad enough, but Cormac is also irritating beyond belief. Despite being a Gryffindor, he isn’t particularly honourable. In fact, he spends most of his time strutting around the castle and bragging about his abilities.

But this doesn’t stop Hermione from kissing him under the mistletoe at Professor Slughorn’s Christmas party. This is particularly strange given Ron wasn’t even at the party to witness the event.

Hermione’s reaction to Ron and Lavender’s romance is one of her lowest moments. She’s meant to be an intelligent girl, yet she spends a large amount of her sixth year behaving like a spoilt brat.