The only place where you should be asked the, "Have you eaten here before?" question is Five Guys. That's because at Five Guys a cheeseburger is actually a double cheeseburger while the little cheeseburger is a quarter pound single patty. I still have no idea why they do that. Also, if you ever go to Five Guys, order the small fires unless you have a 400 pound figure you're trying to maintain. The actual cup of fries can be accurately described as small but they pour a big scoop of loose fries right into the same bag. Still pretty damn good for a national fast food chain.

I'd like to add another context in which the "have you ever eaten here before" question becomes relevant. In Toronto, there are a few restaurants (including an amazing Ethiopian restaurant near U of T) where they do not provide silverware. Ever. Thus, they typically ask if you're a newcomer to ensure you don't throw a loud, public wobbler at the prospect of having to touch your own food...
 
That being said, in non-food-related contexts, "have you been here before" can also be a portent of doom. I foolishly answered "no" to this question at the Eaton Center's Lush (handmade cosmetics/bath products) outlet during the height of the Christmas rush. I was rewarded for my naivete with a ridiculously zealous, 45 minute long "demo tour" of the little store from which I could not escape (the store was packed shoulder-to-shoulder with customers).

I don't often go to Pei Wei on my own specifically because of that manager guy in St. Louis Park. There's kind of a mobster vibe to him, and I prefer to have the social insulation of a default guy - it's the one vestige of sexism I enjoy, restaurant manager guys addressing pointless "customer service" to the guy in the group instead of to me. (It's much less fun at auto repair shops.)
 
Elsewhere, I've spent 20 years perfecting a closed, independent shopping image and a backup chilly "No, thank you/I'm fine, thanks" for emergencies when floor clerks talk to me. I had it so that the clerks at my clothing store just said hello - and sure, in a small store, you're 10 feet from someone, there's no one else there, bells ring when you open the door, the whole primate behavior business, I get the token greeting deal.
 
But recently they are just HOUNDING me - repeatedly asking if I'm finding everything, how am I doing, blah blah blah, despite increasingly irritated and hostile responses from me. It's like the store is one of those playsets with chips and I'm carrying a tag that triggers a recording in proximity to the clerk figure. Here's a hint, clerks:  the people who go shopping to talk to people and have their hands held WILL LET YOU KNOW THAT. You will not be able to shake them. The rest of the people who actually can't find something will probably ask you a question when they need to, as well.
 
When I start coming in with three other people, carrying shopping bags that crinkle suspiciously, then you can implement your intrusive, hypersocial loss prevention techniques on me. As long as I remain a regular customer who buys a lot of stuff and carries a small purse that wouldn't hold a pair of pantyhose, leave me alone.
 
Oh, also, Uptown Chipotle guys - ask me how the food was all you want, there are plenty of tables open for other customers and I'm going to continue sitting here reading. Why don't you ask the loud drunk over there how he is? Likewise, it's only 9:40 PM. You're open until 10:00. Bang the pans and yell "Ai yi yi" all you want (well, actually, stop that, it's embarrassingly stereotypical,) I will not be leaving until 9:55.