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Missing Christmas in CATCHER IN THE RYE
Christmas decoration

Why would a story with an urban setting that takes place during the Christmas holidays hardly mention Christmas until amost the very end of the book:

"While I was walking, I passed these two guys that were unloading this big Christmas tree off a truck. One guy kept saying to the other guy, 'Hold the sonuvabitch up! Hold it up, for Chrissake!' It certainly was a gorgeous way to talk about a Christmas tree. It was sort of funny, though, in an awful way, and I started to sort of laugh. It was about the worst thing I could've done, because the minute I started to laugh I thought I was going to vomit. I really did. I even started to, but it went away. ...It was Monday and all, and pretty near Christmas and all the stores were open. So it wasn't too bad walking on Fifth Avenue. It was fairly Christmasy. All those scraggy-looking Santa Clauses were standing on corners ringing those bells, and the Salvation army girls, the ones that don't wear any lipstick or anything, were ringing bells too. ... Anyway, it was pretty Christmasy all of a sudden. A million little kids were downtown with their mothers, getting on and off buses and coming in and out of stores."

The key phrase above is: "Anyway, it was pretty Christmasy all of a sudden." All of a sudden means what, that Holden's just become aware it's Christmas, that he's briefly coming out of his funk?

Or did Salinger the author suddenly remember that his setting had a hole in it and he needed to throw in a scene recognizing Christmas? It's a throwaway scene that adds nothing to plot or character, except for the phrase, "...a million little kids." So the Christmas scene is for atmosphere, setting. Nine-tenths of the way into the book Salinger remembers it's Christmas and he ought to put something in about it.

A little earlier, he mentions Phoebe's Christmas money and Sally Hayes wants him to come over and trim the Christmas tree with her, but these are oblique references at best.

For ninety percent of the book Salinger barely mentions Christmas. The setting seems unrealistic because of it. There would be decorations all over. Trees lights blinking. Santas ringing bells next to donation pots. Christmas music. The whole shebang.

Phoebe, a ten year-old, doesn't mention Christmas except in relation to her spending money? Sally Hayes, his date, doesn't talk about the Christmas decorations along the street? 

Why did Salinger leave it out? Because he was Jewish? An oversight? Did he regard it as a distraction? 

Maybe omitting Christmas was a technique to make Holden appear so emotionally strung out that he couldn't notice Christmas. Life happens in a setting and what we notice or don't notice about our surroundings says something about how alive or dead or distracted or obsessed we are.

Perhaps the answer lies in the first-person point point of view. We're trapped inside the head of a kid who's in a crisis. The beauty of first-person is that readers get to experience the inner world of the character. The public personna of third-person gets obliterated and the narrator's insides are showing.

The weakness of first-person is that readers are confined to the narrator's perceptions. Holden's so depressed he can't get excited about the omnipresence of Christmas.