I could go on for days about the psychological and social aspects of the customer-server relationship. In fact, I think I literally do go on for days about it in the SMBHBD print zine...which has just been restocked at Microcosm by the way, if you'd like to order one.
There's a great zine called Coffee Shop Crushes, which might be out of print now, where people pour their hearts out about the baristas they've obsessed over and how they've (usually) embarrassed themselves trying to express it. The common theme seems to be that coffee shop crushes are better left to the imagination. To force one into a relationship hardly ever works and the result is usually a) humiliation b) awkwardness and c) having to find a new coffee shop. It's just kind of funny how people are so intrigued by their servers and baristas (it goes the other way too, but that's an entirely different subject).
Unfortunately, I've lived it. My last boyfriend, whom I dated for three years, started out as one of my regular customers (he later also became a coworker - again an entirely different subject). He wooed me by ordering carrot juice every day and sitting for an hour trying to talk to me about music. Always a sucker for a guy who actually recognizes that I actually know quite a bit about music, I finally gave in and hung out with him outside of work. Three years later, cut to me crying on Christmas Day while hauling home the presents my mom bought for him and finding out that instead of skipping my family Christmas to catch up on sleep, he had skipped my family Christmas to go to the bar - with another girl. Granted, this could happen in any relationship, but I think the early dynamics of our server-customer relationship had something to do with it.
There are some customers who use their local coffee shop, restaurant or bar as a dating pool. Once I went out on a date with a different customer (who it turned out was already sleeping with another customer who was a friend of mine) and he spent the entire time trying to get me drunk and talking about how smart he was. He was so smart that after I left him sitting at the table and walked out, he would still come to my workplace, set up shop for a couple hours and try to talk to me. And would come in when I was not working and ask my coworkers for my work schedule.
The point is, I really don't think the customer-server relationship can ever work. Friends, maybe. Drinking buddies, yes. But the conditions are not ideal for anything meaningful because the dynamics are already so fucked up.
I'm mostly writing this for all the lonely middle-aged guys out there who think that barista at Starbucks who remembered your drink or the waitress at Applebee's who gave you a free side of ranch has some sort of attachment to you. I'm sorry to burst your bubble, but she does not. Just please don't even go there for everyone's sake.