I think that
sabby's right on this one: this isn't just your garden-variety narrative about a shell-shocked, dysfunctional war veteran a la
Mrs. Dalloway (although, to be fair,
Septimus Warren Smith is a pretty remarkable character in his own right). The symbolism of the bananafish, in typical
Salinger form, may deliberately be indirect, but at its heart, I think, it's pretty cut-and-dry.
If you read the bananas as a metaphor for
sensual experience and then the bananafish as
consumers of this type of sensation, then one possible meaning may begin to clear up a bit. The bananafish become metaphors for a special sort of person:
hypersensitive, acutely-conscious, overwhelmed by the power of human experience.
Seymour is basically all of the above. His catty, status-obsessed wife clearly doesn't understand him, as evidenced by the conversation that she has with her mother at the start of the story. He himself is clearly so fixated on higher spiritual matters that he is all but unable to interact on a simple, human level with the people around him.
For instance, observe the manner in which he talks to the little girl on the beach,
Sybil (an
excellent choice for the girl's name on
Salinger's part, btw); would you say something that morbid to a nine-year-old? Observe, again, how violently he acts towards the people in the elevator just before he shoots himself - and all that they did was to stare at his goddamn shoes.
Yet this is the same man whose desk at home (as readers discover in
Franny and Zooey) is literally
covered with Zen koans, notable excerpts from literature and insightful, random quotations. He was an exceptionally bright child and clearly fixated enough on spiritual matters to try and instruct his infant brother and sister in the teachings of great religious men before the two even knew their ABCs.
Seymour isn't a person who is out of touch with the world, he's a man who is clearly far too enmeshed
into it. His (admittedly somewhat cheesy) analogy of the bananafish is meant to be self-illustrative, of his own inability to filter experience, and of the self-destructive results of this problem.