WARNING! This not-really-a-review is seriously spoilery. If you have been living in a cave or something and haven't read the book/watch the movie/listen to people discussing about the series, don't read. Just run. Fast. 
 You have been warned 
 Things I like about this book 
 1. The writing, need I say more? Plot, pacing, description...superb. Well, Rowling has almost reached the status 'goddess' in that aspect for me, so, no question for that. 
 2. The way Gilderoy Lockhart was pictured. Makes me think a lot about a case of narcissistic personality I studied in Social Pathology Class. I pity the students for being taught by such an incompetent teacher, though. I know Dumbledore is eccentric but to hire a teacher like this...really, Dumbledore? Really? 
 3. Hagrid's back story. I like Hagrid, although keeping an Acromantula as a pet is a bit too much. 
 4. Dobby! Such a poor, lovable Dobby. He always refered to himself with third person pronoun like he didn't even have his own sense of identity, being a house-elf. I think it's a very nice touch from Rowling. 
 5. Almost everything Ron said and done. From breaking his own wand to belching slug to...well...I just love you, Ron. 
 6. The fact that Harry didn't win the Quidditch cup again despite being the youngest house player for a century. I appreciate that Harry is not flawless, so human. And I love Oliver Wood's reaction to that. Hahaha. 
 7. The introduction to the Weasley family. You'll understand instantly why Harry like this family... I sort of want to grow up with siblings like the Weasleys myself. 
 8. The House Cup is downplayed little by little to give room for more personal and serious motivation to bloom in the next books 
 9. Adults are often pictured as cruel, stupid, and strict while children's freedom and imagination is always the best in children literature (um...most of Roald Dahl's story, anyone?). I love how there are no one-dimensional character and the adults are realistically written. 
 Things I don't really like 
 1. Villain's mistake #1 : Talking too much when you should just kill the protagonist. Why did they always fall to the bait and stall the killing. Although it's understandable because Voldemort don't think Harry will defeat him that way. 
 2. If I were Dumbledore, I would go to the Chamber of Secrets myself and saved my students. I must admit Dumbledore's way of helping Harry was a bit...eccentric and deus ex machina-ish