Yesterday I went through the drive through at the local Starbucks. Pretty simple order, medium sized coffee (what do they call it grande?) with cream and sugar. So the speaker comes on and this over friendly voice takes my order, asks all the same questions and it seems that life is really good from her voice tone. “That will be $1.97”.
Moving along the line up I get up to the wicket. Of course the change tray in the truck has pennies galore so I add 2 cents to the toonie to get my nickel back. The same girl is cheerfully talking stating this and that and I hear the final ‘Thank you’ and ‘Here is your coffee. I’m fine with the chatter, somewhat overdone, but friendly.
I pull forward, stop and begin to pour the paper cup of coffee into my thermos mug. Black coffee, no cream, no sugar. Aaarrrgghhh!
Now the moral of the story — it doesn’t really matter how friendly you are to the customer or if you are Chatty Kathy extraordinaire, if you screw up the order you really haven’t done your job. Pseudo-relationship building comes at a cost.
Tinfoiling 
You must be from New York. To those of us who are impatient, intolerant of mistakes, and anti-social (OK, so maybe it’s just me and not “us”), operational excellence = service.
The reality is that for some customers, friendliness of service will help overcome the occasional (or maybe even frequent) mistake.
But for others, it doesn’t. The marketing challenge is: How do you tell the difference?
It’s not easy, but it doesn’t take a rocket scientist to make some educated guesses. For example, how about assuming that customers who use the drive-up window are time-pressed, and will REALLY resent a mistake made in their order, so let’s put our most efficient (if not friendliest) employees on the drive-up window?
The Tim Hortons by my house has a pretty good drive-thru. I can – almost! – get my large decaf double cream double sweetener without stopping my vehicle! They are not overly friendly, they do not engage me in small talk. Frankly, there’s no time for it. They even have pre-made change piles on their counters for all the twoonie orders. I can’t remember the last time they screwed up my order. For me, drive-thrus are for speed and accuracy. I’m there for coffee, not new friends.