It would seem that Seymour is trying to escape from reality because of the horrors he witnessed and experienced in World War II. One of the reasons he likes talking to children like Sybil Carpenter is that they are too young to know anything about the evils that exist in the world. They live mostly in a world of fantasy and are protected from the harsh realities of human existence. Seymour can retreat into the fantasy world of children and enjoy human contact without having to endure the conflicts that contact with adults so often evoke.
His wife Muriel, who is depicted talking to her mother on a long distance line in their hotel room, is obviously incapable of understanding or sympathizing with Seymour as he is now, although they might have been more compatible before he went to war. There is a glaring contrast between the innocent little girl who could see the bananafish and the mature woman who appears to have no imagination whatever. Seymour would like to escape from the whole world, and the means he chooses is to commit suicide. His death haunts the other members of the Glass family in many of the other stories Salinger wrote afterwards, notably in "Franny" and "Zooey."
Seymour resembles another character created by J. D. Salinger. That is Holden Caulfield in The Catcher in the Rye. Holden is also on the verge of a nervous breakdown, and the only person he can relate to is his little sister Phoebe, although he makes a desperate effort throughout the novel to relate to older people. Like Sybil Carpenter, Phoebe still lives in that enchanted world of childhood which Holden is being forced to leave by the onset of maturity.
Most of the stories Salinger published in his anthology titled Nine Stories, deal with precocious children.