"Hello, we are Those People Who Give the Barista Step-by-Step Guides That Must Be Followed Exactly to Make Their Drinks."

I'm the man who comes up to the register and begins the following conversation:

CUSTOMER: I'd like a latte...
BARISTA: (ringing it up) OK, that'll be $2.89.
CUSTOMER: ...and this is how you're going to make it.
BARISTA: (stops, looks up) Huh?
CUSTOMER: Now, I want three shots of espresso, but I don't want them to be bitter, so I want you to pull them after you prepare the rest of the drink.
BARISTA: (pauses) Well, OK, we can do that. So, that'll be...
CUSTOMER: ...and make sure you use 2% milk. And when you steam it, I want you to make sure it's at least 190º.
BARISTA: That's pretty hot... (shakes head) Fine. That'll be...
CUSTOMER: (impatient) I'm not finished. (pauses)
BARISTA: (makes awkward eye contact) ...what else do you want?
CUSTOMER: Put three pumps of vanilla in there. Not the new vanilla syrup you started using about two months ago, pull out the old good stuff.
BARISTA: (amazed) I...don't really think we have any more of the old syrup.
CUSTOMER: (insistent) You do. I always get it.
BARISTA: (unconvinced) Well...OK then.
CUSTOMER: Steam the 2% milk first, to 190º, and then put in the syrup. Three pumps. The last time I came in the worker just put in two pumps and it was awful.
BARISTA: (forced smile) Yes sir. Anything other instructions?
CUSTOMER: Yes. (The barista muffles a groan, while other baristas have stopped and wait for the instructions on how to make the drink.) When you put the three freshly pulled shots into the drink, make sure you stir it well. About ten times should do it. But don't stir too long or it'll get all bitter.
BARISTA: (confused) All right. (resolute) Anything else?
CUSTOMER: (pauses, thinks) No. That should do it. (cashier sighs, other baristas begin making the drink) How much do I owe you?
BARISTA: That'll be $3.46.
CUSTOMER: (angered) You said it would be $2.89!
BARISTA: Well, that was before you asked for shots of syrup.
CUSTOMER: (miffed) Fine. Forget the shots of vanilla.
(The baristas have just put the vanilla shots into the cup of steamed milk; they audibly groan and throw it away, then start remaking the drink.)

It's very nice to meet you.