Here is an example of Holden's self-awareness from the opening paragraph of Chapter 3 in The Catcher in the Rye.
I'm the most terrific liar you ever saw in your life. It's awful. If I'm on my way to the store to buy a magazine, even, and somebody asks me where I'm going, I'm liable to say I'm going to the opera. It's terrible. So when I told old Spencer I had to go to the gym to get my equipment and stuff, that was a sheer lie.
Holden feels it was "awful" and "terrible" to tell Mr. Spencer a lie--but this is something we all do. We call them "white lies" because they don't really hurt anybody. Holden had gone to visit Mr. Spencer because the old man was one of the few who had been kind to him at Pencey. Spencer recognized the boy's intelligence and writing skill. Holden also felt sorry for the old teacher because he was sick. But the visit became an ordeal when Spencer began to lecture and hector and cross-examine. Holden felt that he had to get out of there. He says:
Boy, you can't imagine how sorry I was getting that I'd stopped by to say good-by to him.
Spencer is actually the only person Holden says good-by to before leaving Pencey. This is sad. It shows how little the students and teachers liked him. Throughout the story there is only one person who genuinely cares about him: his little sister Phoebe, like many little girls, really loves and worries about her big brother.
A good example of self-deception is also to be found in Chapter 3, where Holden talks about his tastes in reading.
I'm quite illiterate, but I read a lot....I read a lot of classical books, like The Return of the Native and all, and I like them, and I read a lot of war books and mysteries and all, but they don't knock me out too much.
The hypersensitive Holden has a bad opinion of himself. It might be the result of having been expelled from three or four schools, including Pencey, where he flunked four out of five courses. From his discussion of his reading habits in Chapter 3, it is obvious that he reads more than anybody else in his school. Why should he consider himself illiterate? Probably just because he knows there are many famous books and authors he has not yet read. In other words, he only wishes he could read more. He is only sixteen, and it will be a long time before he can read all the great works by British, American, French, Russian, and other great authors. And in the meantime his interests will be changing and more good books will be coming out.
Holden is continually fantasizing about how he would like to live. In a touching passage in Chapter 22, he tells Phoebe:
"Anyway, I keep picturing all these little kids playing some game in this big field of rye and all. Thousands of little kids, and nobody's around--nobody big, I mean--except me....What I have to do, I have to catch everybody if they start to go over the cliff--I mean if they're running and they don't look where they're going I have to come out from somewhere and catch them. That's all I'd do all day. I'd just be the catcher in the rye and all.
Holden is unrealistic and impractical. He is jeopardizing his future by getting expelled from one school after another, and not applying himself in those schools while he is there.