the-ballad-of-peter-pettigrew:

Book Harry: sassy little shit, an athlete constantly on the Quidditch pitch, natural leader
Movie Harry: doesn’t play much Quidditch, stares dramatically into the distance with flared nostrils. “Who am I, Hedwig? What am I?”

Book Ron: heart and soul of the trio, understands Harry like no one else, awesome sense of humor, terrified of losing Harry, understandable inferiority complex, says the line “If you’re going to kill Harry you’ll have to kill us too!” as well as saving them all from strangulation by Devil’s Snare with the line, “Are you a witch or not?” (hem hem, very cool under pressure while Hermione sometimes isn’t), is the primary source of Wizarding and Ministry know-how, defends Hermione when Snape bullies her (“You asked us a question and she knows the answer! Why ask if you don’t want to be told?”), described by Rowling as “easy to love”
Movie Ron: Eats food and makes moody faces, completely panics in the face of Devil’s Snare and needs Hermione to save him, supports Snape’s talking-down of Hermione (“He’s right, you know”) and generally sits in the shadows until the next comic-relief scene is needed

Book Hermione: brightest witch of her age, always thinks she’s right and usually is, not particularly attractive, socially awkward, refuses to admit to most of her emotions and doesn’t understand Harry as well as Ron does, but nevertheless amazing in her own unconventional way
Movie Hermione: brightest witch of her age, conventionally attractive, literally a goddess, has a lot of awesome lines like “If you’re going to kill Harry you’ll have to kill us too!”, comfortably uses Voldemort’s name from the second movie onwards, highly perceptive to all things emotional, acts as Harry’s personal counselor and has heart-to-hearts with him while Ron sits in the background eating or sulking

Book Ginny: witty, popular, exciting, hates to be left out of things her older brothers get to do (and makes a huge fuss over it when she can’t), tough, writes Harry an audacious love poem as an eleven-year-old, trains herself to be an incredible Quidditch player, mischievous, a terrific liar and fighter, puts Harry in his place with her snarkiness, brave, gentle, badass and kind
Movie Ginny: feeds Harry a pastry