Almost everyone has a favorite quote; something they find especially touching, thought-provoking, intelligent, or just funny. Some people's favorite quotes are ironic, some are serious, and some just make absolutely no sense. Previously, true quote-fanatics had only a limited number of ways to display their particular fondness for a quote: t-shits, bumper stickers, maybe the occasional poster. With the advent of the Internet however, quote enthusiasts have virtually limitless ways to display their love for the inspirational words of others: Twitter feeds, Facebook statuses, blogs, email signatures.
A person's favorite quote can offer a lot of insight into his personality. If a man's favorite quote comes from Dude Where's My Car? it implies something very different than if his favorite quote comes from Citizen Kane. The same applies to books. A man above of the age of fifteen who is obsessed with Catcher in the Rye quotes is probably never going to grow up and is most likely unnecessarily judgmental. It's not okay to idolize Holden Caulfield after tenth grade, though it's always okay to idolize J.D. Salinger.
Shakespeare quotes say something else entirely. They may say that the person is well-read and a true fan of the Bard. Some people truly love Shakespeare and believe that the answers to all of life's questions can be found in those plays. There are also some people who memorized a few key Macbeth quotes ("Double double toil and trouble" perhaps) and trot them out whenever possible because they assume that everyone equates Shakespeare with intelligence. (Not to say that they don't, but intelligence is hopefully not quite that easy to define.)
Someone who loves Jane Austen quotes is probably a woman, and is actually less likely to be a poser than someone quoting Shakespeare. Of course there are true Shakespeare lovers and Austen posers, but generally someone who is quoting Pride and Prejudice at a dinner party has likely read the novel six or seven times, and owns the six hour mini-series on both VHS and DVD. Most readers respect Shakespeare, but Austen lovers truly love Austen.
Great Gatsby quotes are a safe bet for someone wanting to sound learned, but not like he's faking it. Almost everyone, from the high school AP English student to the seasoned reader, agrees that The Great Gatsby is a truly great novel, one that improves upon every additional reading, but it's also very accessible. A junior in high school may enjoy it in an entirely different way than a literary scholar, but the truth is that they both enjoy it, and that is really a tribute to Fitzgerald's writing. The opening and closing lines of the novel are amongst the most-quoted, and are arguably some of the beautiful lines of American prose ever written.
The worst offender of all is, of course, someone who passes a great writer's quotes off as his own. If that's the case, it doesn't matter which novel or author the offender chooses to rip off. It's wonderful to pay tribute to the great minds of the world, it's another to steal from them.