I'm the most terrific liar you ever saw in your life. If I'm on the 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. (3.1)
Point of view is HUGE in The Catcher in the Rye. Holden's perspective on matters is the substance of the novel; more than the events themselves, we're interested in what Holden thinks of the events/people/places/weather/dead mummies and how he presents them to us – a.k.a., his point of view. What makes it so much fun is that we're never sure how much to trust him. While Holden calls essentially everyone in the book a "phony" at some point or another (with the exceptions of Jane Gallagher, his brother Allie, and his sister Phoebe), he himself is a constant liar.
He never tells the truth to people who ask, so we aren't sure if he's snowing us, as well. It might not be an entirely conscious snowing – he's certainly not sitting back and trying to deceive us – but putting spin on everything seems to be a real part of his persona. (Think about when he tells us about how he puked that night at the Whooton school after indulging in a bottle of scotch; he says he only threw up because he made himself, not because he had to. He's not trying to lie to us, but he's convinced himself (and so tries to convince us) because he wants to think he can hold his liquor.) Because we're confined to Holden's point of view, we can't be sure about him or the people he describes as moronic phonies. Maybe they're nice and more intelligent than described.