"What would your head have been doing in Hogsmeade, Potter?" said Snape softly. "Your head is not allowed in Hogsmeade. No part of your body has permission to be in Hogsmeade."
"I know that," said Harry, striving to keep his face free of guilt or fear. "It sounds like Malfoy's having hallucin--"
"Malfoy is not having hallucinations," snarled Snape, and he bent down, a hand on each arm of Harry's chair, so that their faces were a foot apart. "If your head was in Hogsmeade, so was the rest of you."
"I've been up in Gryffindor Tower," said Harry. "Like you told--"
"Can anyone confirm that?"
Harry didn't say anything. Snape's thin mouth curled into a horrible smile.
"So," he said, straightening up again. "Everyone from the Minister of Magic downward has been trying to keep famous Harry Potter safe from Sirius Black. But famous Harry Potter is a law unto himself. Let the ordinary people worry about his safety! Famous Harry Potter goes where he wants to, with no thought for the consequences."
Harry stayed silent. Snape was trying to provoke him into telling the truth. He wasn't going to do it. Snape had no proof--yet.
"How extraordinarily like your father you are, Potter," Snape said suddenly, his eyes glinting. "He too was exceedingly arrogant. A small amount of talent on the Quiddicth field made him thin he was a cut above the rest of us too. Strutting around the place with his friends and admirers... The resemblance between you is uncanny."
~Prisoner of Azkaban, Ch. 14 "Snape's Grudge"
This is one of my favorite quotes, because it starts out hilarious and ends very seriously with some insight on Snape's past. I've always loved the "no part of your body is allowed in Hogsmeade" thing... It makes me wonder how that conversation between Snape and Draco went down.
And I always get really mad at Harry when I read this, because Snape isn't even being unjustifiably cruel. He has a valid point, and that is how Harry seems to be the only person who doesn't care about his safety, and also the only person that ultimately controls it. Snape must have been way angrier than he was letting on here, because he must hate it so much that he can't help but worry over the life of a kid (even when it's not in his control) that insists on putting himself into possibly dangerous situations. He would obviously hate anyone that puts Harry's life in danger, and that includes Harry himself.
And of course, there's everything about James... God, I feel so sorry for Snape having to deal with Harry.
On another note, this is my 200th post! ^_^