There is no way that Harry Potter would have survived past his first year at Hogwarts without the help of Hermione Granger. Her intellectual ability has gotten our protagonist out of countless dangerous situations and saved his life numerous times, even at the age of eleven, while maintaining perfect marks on her school work. In short, Hermione is a complete badass, and that is shown consistently throughout the book (or if you're lazy, movie) series.
1. When she told us it was LeviOsa, not LeviosA.
Hermione's unwavering confidence in her knowledge and ability to understand academic concepts so easily is amazing in and of itself, but she is quickly able to identify exactly what Ron is doing wrong, showing a complete mastery of the charms class.
2. When she confidently introduced herself to the two boys that would become her best friends.
It had to be hard for Hermione to go to a wizarding school, having only just found out she is a witch upon acceptance, and to walk to two of your peers and introduce yourself is daunting enough without that added burden.
3. When she kept trying the recipe in Year 6 Potions, despite Harry telling her a trick.
I don't know about Hogwarts' Academic Integrity Policy, but if they have one, Hermione would be a model student (I wish I could say the same for Harry).
4. When she told Harry and Ron her honest opinion.
Hermione loves her friends, but that does not mean that she will lie to them to spare their feelings.
5. When she punched Draco in the face.
I am so glad someone made this a gif, so I can watch it over and over. This is one of the most satisfying parts of the series, and only solidifies Hermione's place in the Bad Ass Hall of Fame.