AUTHOR'S NOTE: I wrote this just after I watched Deep Breath in an attempt to capture the new Doctor's personality. One Series 8 later and I still reckon I did pretty well, but read it and judge for yourself.
Humans. Shopping and money and coffee. How the hell does one get coffee?
The Doctor marches along the high street, trying to look fearsome and imposing to hide the fact that he fears this more than any Dalek. Daleks, he can understand and he can fight. Day-to-day human life... he's aware that he saves this on a regular basis, and he's sure they enjoy it, but him actually living one? The thought makes both his hearts tremble. It must be so boring! No wonder they need coffee!
There! A shop with a picture of a cup of coffee on the outside. Unless humans have evolved a pictographic language of which he has no understanding and in which a cup of coffee represents total universal destruction (or something), that is a fairly good sign to notify the passerby that one will find coffee within. So within is exactly where he goes.
"Get me coffee!" he proclaims. People stare. He doesn't care.
There's a young man standing (almost cowering) behind a counter, looking at him like prey at a predator. "Um. What type of coffee? Sir?"
"Oh, complications!" No time for this! He may be a Lord of Time, but he won't stand for wasting it. "Just get me coffee!" Hesitates - "No, no, two coffees. I think I need one as well, now."
Eyes wide like twin moons, the man nods and gets to work. Coffee comes out of the coffee machine. Steaming coffee in two coffee cups. Coffee, pushed his way!
There's a pause. The man stares at him. He stares at the man. Then the mouse of a human squeaks: "That'll be two pounds forty... please?"
What?
Oh no. He's not having any of that.
"Listen to me, young man! Young..." Oh, he has a name tag! That's handy, saves him the trouble of thinking up fitting nicknames. "Now you listen up, young Sanjay! I am the Doctor. I'm over 2000 years old. And I have saved the entire population of your planet far too many times to count. Daily, in fact, though days mean nothing to a time traveller. What might be the most important thing you do this day, perhaps in your entire life, is giving me this coffee. Because the next time I have the fate of the entire universe in my hands, and that could be mere minutes from now, you don't want me falling asleep in the middle of it. Coffee. Now."
The man flees through the door at the back. No, 'Sanjay' doesn't fit him at all. 'Mouse' works far better.
At least this leaves him free to take the coffee and go. Money? Who needs it?
He has coffee. And, in a TARDIS trip's time, he'll have Clara too. That's all he needs.