1.When Oliver Wood releases the Snitch while teaching Harry how to play Quidditch, he immediately loses sight of it, but Harry keeps his eye on the Snitch, highlighting his future talent as a Seeker.
2.In Snape’s death scene, there's a Gryffindor scarf hanging up in the background, a reference to his bravery and Dumbledore saying he “sometimes thinks they sort too soon” in the books.
3.The ways Harry, Ron, and Hermione wear their scarves and ties reflect their personalities.
4.In Sorcerer's Stone, there’s a portrait of Anne Boleyn (who Henry VIII accused of witchcraft) in Hogwarts.
5.In Prisoner of Azkaban, the bartender makes a bottle disappear.
6.What Sirius tells Harry when he says goodbye in Prisoner of Azkaban foreshadows Harry's use of the Resurrection Stone in Deathly Hallows Part 2.
7.And what Luna tells Harry while looking for her shoes after Sirius's death also foreshadows the use of the Resurrection Stone.
8.As each horcrux is destroyed, Voldemort’s robe becomes more faded and dirty looking.
9.Hermione's hair grows throughout Deathly Hallows Part 1 to show how long she, Ron, and Harry have been traveling in search of horcruxes.
10.In Tom Riddle's room in the orphanage in Half-Blood Prince, there's a picture of some cliffs. Those are the same cliffs where Dumbledore and Harry travel to collect the locket, one of the seven horcruxes.
11.When Harry reveals that he's alive in Deathly Hallows Part 2, George turns to excitedly tell Fred, who's normally always next to him.
12.In Deathly Hallows Part 1, the fake name that Hermione gives to the snatcher is the name of Percy's girlfriend in the books.
13.In Goblet of Fire, there's a Deathly Hallows–shaped device visible in Dumbledore's office.
14.The Warner Brothers logo gets more tarnished and decayed throughout the series.
15.In a flashback in Order of the Phoenix, Sirius says, “Nice one, James,” when James disarms Snape. Later, after Harry disarms a Death Eater, Sirius says the same thing.
16.When McGonagall attacks Snape in Deathly Hallows Part 2, he knocks out the Carrows and steals their wands before escaping.
17.And finally, Chamber of Secrets has a post-credits scene that reveals the fate of Gilderoy Lockhart.
Want to be featured on BuzzFeed? Follow the BuzzFeed Community on Facebook and Twitter!
Note: Submissions have been edited for length and/or clarity.