The Scottish philosopher David Hume once said, "Beauty in things exist in the mind which contemplates them." I write that not to introduce a writing on beauty or the mind but merely to impress you. Quoting the famous yet not well-known (like Hume, David but not like Clooney, George) is a wonderful pretense. If I quote Hume or Descartes or Tennyson, it creates the illusion that I'm well versed in their thoughts and writings. I therefore must be a pretty erudite guy. I mean you wouldn't assume that I just came across the quote somewhere and know little or nothing else about the author.
Names like the aforementioned are ideal for the impressive quote. They're writers, philosophers, poets whose names have a vague familiarity. It's all well and good to quote Shakespeare or Lincoln but come on, everybody knows all about THOSE guys. No, to put on airs you need the vaguely familiar. Foreign names are good too like Flaubert or Schopenhauer. People who read translated stuff have got to be brainy. Or maybe you read it in the original language!
Of course referencing such people in conversation can have the same effect. And really, who's going to call you on it?