There's an excellent and accurate article right now on Slate.com by Mark Oppenheimer on being a snob. How to define a snob? Let's say, perhaps: someone who has confused an aesthetic for an ethos. And undoubtedly I am a snob, if a self-aware one. (But then it's possible that all snobs are in fact highly self-aware, in that they cannot fail to acknowledge that their tastes are not those of the mainstream -- if their tastes were mainstream they would not be snobs; if they were unaware of this divergence, they would merely be eccentrics and not snobs at all.)
Snobbery as we generally understand it is class-based, but it is not only a phenomenon of the upper class. Any person or subculture acutely concerned with the appearance of authenticity partakes in snobbishness, I think. Snobbishness is always aspirational, but it is fanatical about avoiding the appearance of aspiration. One should have been born with an impeccable set of tastes; all one's choices must appear to emanate from the core of one's being – indeed they should hardly be choices at all, they are simply the natural consequences of one's way of life. This is why snobbery is much easier to pull off for the upper-class: they may have the advantages of not actually having to work very hard and of being tutored in good taste by those within their milieu.
The working-class snob has it harder. She can turn to those subcultures that define themselves in opposition to what one might call the “preppy” strain of snobbishness: punk rock, say, or the thug culture in which the ultimate accessory and badge of authenticity is a gunshot wound. But the bookish and shy are unlikely to successfully pass in such a scene. Instead, one ends up cobbling together an aesthetic from bits of books, movies, magazines, the elite of previous eras, and comes to develop an idiolect of signifiers which may overlap with those of other snobs but never connect one to a larger snob culture. One takes the Pillow Book in which one has scribbled hastily over the years and turns it into doctrine. For the working-class snob, this may resemble the Ten Commandments more than a style guide: without a unified model to aspire to, one works mainly with negative space to create a picture of the appropriate. No, one must not hang a television on a wall, or museum-shop reproductions of famous works of art. One must not wear Uggs or Crocs, or sweatpants, or sea-foam green, or anything with a prominent logo. One walks down every street saying no, no, goodness no, interrupted by the occasional yes, an approving nod in the direction of the object that knows its place, the person who understands how to behave.
Oppenheimer worries about the effects of his snobbishness on his young daughters, and it can certainly be toxic to family life. My childhood years were spent cringing at and railing against the bad taste of my surroundings. There were so many sources of outrage: the plastic bouquets at my father and stepmother's wedding, the enormous “antique,” “distressed,” “Asian” print of a tiger that my mother brought home from Meijer for our living room, the nattering television shows that nobody was really watching but which nobody would ever let me turn off.
Under the tyranny of my taste, over the years my mother has made steps towards snobbishness herself. Her tastes in music, movies and reading material have by this point all been heavily inflected by my own; she is surprised when I do not agree with her, that she can have picked up on the details of my snobbishness without discerning its larger shape. As a teenager, these near-misses irritated me more than if she had wholly ignored my preferences. She was too clearly trying. It ruined the whole thing.
In his essay Oppenheimer mentions, almost offhandedly, “the tragedy of the snob, which is that he needs to think he is grand just to think he is worthwhile.” When love of God or country or money are not enough to shape one's life, other standards are required. The snob knows that, judged on his or her inner qualities alone, she will always be sorely lacking. Better to locate success in the arbitrary, the anti-pragmatic, the obscure. One has so much less competition there, there where the appearance of competition itself is enough to disqualify any competitor. The sovereignty of the snob remains intact.