"So I suppose you think that's a reward for breaking rules?" came an angry voice from just behind them. Hermione was stomping up the stairs, looking disapprovingly at the package in Harry's hand.
"I thought you weren't speaking to us?" said Harry.
"Yes, don't stop now," said Ron, "it's doing us so much good."

Harry Potter and the Philosopher's Stone - Chapter 10 : Halloween
See this quote in the Pensive -