If reading is a drug, then Proust is the literary equivalent of an LSD trip.
You read Proust, and you see writing and the world in an entirely different way. You've glided through the doors of perception, tuned in, experienced the Divine Truth.
Then you wake up the next morning and try to explain the experience to someone.
And you cannot find the words. And you start thinking, what was it that I really experienced? Has my reading comprehension really degraded that much? Do I really understand English?
Although I'm about 2/3 of the way through In the Shadow of Young Girls in Flower, I couldn't tell you the plot. I think Marcel is going from adolescence to adulthood. He breaks up with Gilberte. He goes to a hotel. He meets a few snobs. He acts like a cry-baby.
But he's at his most hallucinogenic when he reflects on life.
Here, for example, is a striking passage about artists and friendships:
Friendship is a dispensation from this duty [to live for the artist's self], an abdication of self. Even conversation, which is friendship's mode of expression, is a superficial digression which gives us nothing worth acquiring. We may talk for a lifetime without doing more than indefinitely repeat the vacuity of a minute, whereas the march of thought in the solitary work of artistic creation proceeds in depth, in the only direction that is not closed to us, along which we are free to advance--though with more effort, it is true--towards a goal of truth. And friendship is not merely devoid of virtue, like conversation, it is fatal to us as well. For the sense of boredom which those of us whose law of development is purely internal cannot help but feel in a friend's company (when, that is to say, we must remain on the surface of ourselves, instead of pursuing our voyage of discovery into the depths)--that first impression of boredom our friendship impels us to correct when we are alone again, to recall with emotion the words which our friend said to us, to look upon them as a valuable addition to our substance, when the fact is that we are not like buildings to which stones can be added from without, but like trees which draw from their own sap the next knot that will appear on their trunks, the spreading roof of their foliage.
Now, I ask you: How can you explain this passage to someone, without destroying the experience of actually reading it? That, to me, is what makes Proust a writer like no other. His prose can only be experienced by the reading of it. Not by making it into a film, not by reading a book review or Cliff's Notes or a few chapters. No cheap bottle of Ripple or bong hit will do. You have to lay yourself open to the entire experience to get the buzz.