Sherlock hadn't really been expecting anyone to attempt to talk to him that morning. He should have known better, though. And he really wasn't too terribly surprised when the man behind him tapped on the shoulder. Seriously, though, didn't people have better things to do with their time? Like waiting in line, minding their own business.
He turned around to face the man behind him, and arched an eyebrow at him. "The same goes for you, you know. It's not life or death when you get your coffee. It's not like they're planning on running out anytime soon." It was Starbucks after all. Running out of coffee would hurt their business. They were a coffee shop.
He then moved to face the front of the line once more. Because he was grumpy without his caffeine.