What the hell is a Barista anyway?

So, a new hotel has opened in our neighborhood, complete with the requisite Starbucks, a sports bar and a cute little ice cream parlor on the first floor. Husband and I decided to take a leisurely walk to the hotel (it's named after a certain jailbird heiress and her family) to partake in an after-dinner ice cream cone. The walk was lovely, the ice cream parlor and its staff were adorable, and husband's double scoop of cookie dough looked scrumptrulescent. I was in the mood for an iced coffee, so I strolled over to Starbucks and ordered a decaf grande whatever. The barista (gimme a fricken' break already) informed me that, regrettably, they were unable to produce a decaffinated iced coffee this evening. I scrunched up my nose, pointed to the menu behind the counter and shrugged. The barista followed my gaze, confirmed that, yes, they should have decaf available, but they don't. That was it. No further explanation. I stared. He stared. I squinted. He sweated. He asked what else I'd like. I said 'nothing', and I actually said thank you, even though what I wanted to say would have violated Hating The Player's no-cuss clause. So, off we went, Husband with his delicious cone and I with my, well, my suddenly deep, deep hatred of Starbucks and its useless baristas firmly established.