Oh my gosh so many damn emotions this book. 
 - We learn how and why Voldemort has been capable of living after going through so much. Horcruxs which contain small fragments of Voldemorts soul in each of them. We must destroy all the Horcruxs in order to destroy Voldemort! 
 - The battle at Hogwarts...(view spoiler)[SO MANY FEELS. At first Dumbledore being brutally murdered by freaking SNAPE. Never should've trusted that many. Only for Hagrids hut to catch on fire and for Fang to nearly die! (hide spoiler)]Such an intense scene. 
 - Fleur and Bills love after the accident. The way the Weasleys finally realized that Fleur is more than just her appearance and that her love for Bill runs deep. 
 They're no longer teenagers dealing with mundane things. Voldemort is growing stronger as well as his following of death eaters. The books are taking a darker turn as the end is nearing. The students are all growing older and taking on more serious aspects of life.