In case anyone didn't know, "Garçon!" is *not* how you call a waiter to your table in France - it's old-fashioned and is considered very rude. It literally means "Boy!" As an insult for Kurt it belittles him while using a language that has long been almost his alone on the show, plus a lot of people in the café may well not even twig that the word she's using is rude (in that context). On a meta level it also recalls that Kurt is now in the position of the wait staff that he used to snap his fingers at.

I love this commentary. At first I just read Kitty's, "Garçon!" as a distancing thing, emphasizing how wrong that context is for Kurt. He's mentally so far away from them that high school is starting to sound like a foreign language. (Remember, Glee almost never depicts the way things are. Rather, it literalizes the way things feel.)

But I love the way you tie in Kurt's relationship with class -- the fact that he's on the other side of his own pretentious finger-snapping and affectation. Now that he's on the other side, he can see it for the affectation it is, the better to cast it off. Time to cast off childish things. I can picture him snarking to himself in the corner, "Suis aucun garçon, you cultureless twit," but then, "Alors...?" If you object to being called "boy", Kurt, then it's time to man up.