Hello! I'm Ivy Grey!
When Harry, Ron and Hermione get stuck in Devil's Snare, Hermione's dialogue is my number one favourite!
"Devil's Snare, Devil's Snare... what did Professor Sprout say? -- it likes the dark and the damp---"
"So light a fire!" Harry choked.
"Yes -- of course -- but there's no wood!" Hermione cried, wringing her hands.
"HAVE YOU GONE MAD?" Ron bellowed. "ARE YOU A WITCH OR NOT?"
Said by Professor Albus Dumbledore, this line is a also a top favourite:
"Second- to Miss Hermione Granger... for the use of cool logic in the face of fire, I award Gryffindor house fifty points."