Harry Potter and The Chamber of Secrets

"Dobby gave him a tragic look."

"No Muggle [human] would admit their key keeps shrinking--they'll insist they just keep losing it.  Bless them, they'll go to any lengths to ignore magic, even if it's staring them in the face . . ." --Mrs. Weasley

"Snape looked as though Christmas had been cancelled."

"My late lamented lords, ladies, and gentlemen, it is my great sorrow . . . " --Nearly Headless Nick, a ghost, to a room full of ghost peers, at his 500th deathday party

In anticipation of my Vocational & Occupational Direction class this fall: 

"'Depends where you want to go, Harry,' he said.  'It's never too early to think about the future, so I'd recommend Divination.  People say Muggle Studies is a soft option, but I personally think wizards should have a thorough understanding of the non-magical community, particularly if they're thinking of working in close contact with them--look at my father, he has to deal with Muggle business all the time.  My brother Charlie was always more of an outdoor type, so he went for Care of Magical Creatures.  Play to your strengths, Harry.'"  --Percy Weasley

Ahh.  Securely-attached authority:

"'I seem to remember telling you both that I would have to expel you if you broke any more school rules,' said Dumbledore.  Ron opened his mouth in horror.  'Which goes to show that the best of us must sometimes eat our words,' Dumbledore went on, smiling."

"It is our choices, Harry, that show what we truly are, far more than our abilities." --Dumbledore

And my favorite is Rowling's portrayal of the Mandrakes, magic plants which are carefully cultivated into adulthood by Professor Sprout in order to be used as a cure for (literally) petrified students at Hogwarts.  This also goes as an ode to my current Counseling Children & Adolescents Class:  

"Madam Pomfrey was pleased to report that the Mandrakes were becoming moody and secretive, meaning that they were fast leaving childhood."

and later,

". . . and in March several of the Mandrakes threw a loud and raucous party in greenhouse three.  This made Professor Sprout very happy.  'The moment they start trying to move into each other's pots, we'll know they're fully mature.'"