It's funny the way that the story is set up in this second section, almost with an omniscient narrator and yet our Marcel is nowhere to be found. But is this really the case? Where I realize in a very real sense that they are two different people, Marcel could easily grow up to be this man who he admires greatly. The primary characteristic I notice that they both share is their insatiable heart.
I think this inability to find satisfaction in regular pleasures is very closely related to the idea of the external versus the internal. The external being, for example, an enjoyable social gathering such as when Marcel begins regularly attending the Verduin's parties with Odette. On page 126, it is noted that Swann often shows up late to the parties (and to see Odette) as if to emphasize, if only to himself, his own disinterest in the event. Happiness and pleasure are not the same as contentment and satisfaction. And though these parties may bring the prior, the value is fairly low to Swann for this reason.
The internal, as explained on page 217 where Swann describes his reaction to a particular phrase in Vinteuil's sonata, is where the beauty is not necessarily the thing itself (the external stimuli) but the emotions and thoughts it triggers into him when he hears it. Much like Marcel's madeleine, but rather than a memory being brought back, it is feelings and future ambitions. He continues to seek it out to trigger this reaction knowing that it is fleeting. I think it's the very finite nature of the piece causing it and the dependence on the stimuli (which can be extremely erratic)to elicit these rare and fragile feelings that give it such a high value to Swann. To summarize, “the ideal is inaccessible and happiness mediocre” (230).
The inability to feel satisfied also lends itself to the egotistical natures of Swann and Marcel. We can see this egotistical notion of value on page 232 where Swann begins to notice a more real beauty in Odette only where her features are that of Botticelli's work. Previously he found her to be almost repulsive, her beauty so ordinary as to make her seem plain. Odette reminded Swann, if only vaguely at first, of a subject captured by Botticelli, an artist whose work Swann admired. If Botticcelli had found beauty worth displaying in someone who looked, if only slightly, like Odette, surely that would mean that it was a higher beauty than a common person would see and one now worthy of Swann's admiration. His inability to obtain the same daily satisfactions as "normal people" make him deserving of even finer and finer things. This egotism isn't meant to be cruel, however, the expectation being so ingrained into his psyche as to become his nature.
Lastly, I would like to note that, in Marcel's search for truth, I think it's important that the “flawed” natures of our subjects are examined. From the sadistic nature of the lesbians to Francoise's cruel streak, (pg 125) noting she could more easily cry for a stranger than an acquaintance, to the very obvious vanity of Marcel and Swann, what we are observing is a more human behavior. Particularly in this time period and with individuals of this class where propriety and manners take precedence over true intimacy and real thoughts were less easily discernible. It stands to reason that that within us which we least like to show is what is most unkempt, imperfect, offensive and yet it is what makes us up. And, given Marcel's near obsession with truth (or is it Truth?) it is not surprising that he is so internalized as this is where his truth will come from.