Biscuits:
"John, what is this?"
"What is what?"
"We're out of biscuits." Sherlock shook the box.
"And?"
"I can't THINK without them, you know that."
This was the first time John had heard anything about this.
"What do you want me to do about it?"
"Run down and buy some for me."
"Money?"
"Coat pocket."
John did so, because he knew there would be no peace until Sherlock's request was filled.
But when he got back, something was waiting for him.
"Tea?"
"Cold outside."
"And it's safe to drink?"
"Perfectly."
"Well then…um…thank you, Sherlock."
"I was BORED. Where are the biscuits?"