You can depend on some things to be absolutely true in the Harry Potter universe: at least once per movie Harry’s scar will make him cringe, Ron will do something to hurt the feelings of the opposite sex, and Hermione will save the day. She’s been a precocious overachiever since her first first footsteps into Hogwarts. Well, long before then actually. At first, she seemed like an insufferable know it all. That’s the first impression other characters communicate, so it’s the first reaction viewers (and readers) have. But think about it. She doesn’t flaunt her knowledge. She’s just eager to show that she’s spent an insane amount of time studying. I like this approach much better than hiding behind a book and pretending not to know the answers.
It’s a good thing Hermione had her nose stuck in school books so often. Her endless knowledge and impeccable memory has saved the skins of her friends, Hogwarts and possibly the world on several occasions. In face, so many times that it’s hard to pick her best moment, but not impossible. When the main trio go on the run in ‘The Deathly Hallows,’ they wouldn’t have made it far without Hermione. She had the presence of mind to carry along a bag with an undetectable extension charm – what gamers call a bag of holding. She packed it with everything from changes of clothes to tents to survival tools like Essence of Dittany. She knew the enchantments and spells that would hide their camp and protect it from unwanted visitors. Death Eaters, snatchers or worse would have found them after their first Apparition.
She could win a wizarding history trivia contest, she keeps her friends safe, and she can more than hold her own in a fight. If I were a follower of You Know Who faced with Ron, Harry and Hermione, I would try to take out Hermione first.