Holden strikes up a conversation with his cab driver, who's named Horwitz, then finally asks about the ducks in the Central park lagoon. Horwitz becomes angry at this stupid question. Horwitz shouts that fish have it worse than the ducks, but that they survive because "it's their nature."
This is the second time an adult rejects Holden's childish questions. Horwitz's explanation of the fish's ability to survive winter contrasts with Holden's inability to adapt to his surroundings.
At Ernie's, the scene disgusts Holden: it's filled with the "phonies" from fancy colleges and prep schools whom he despises. In one conversation, Holden overhears, a guy he refers to as "Joe Yale" describe a fellow student's suicide attempt while trying to feel up his date under the table.
Again, society is phony and "Joe Yale" is undeniably an insensitive jerk. But while most people could shrug this off, Holden can't. Phoniness eats at him and makes him furious.
A girl named Lillian Simmons, who used to date D.B., approaches Holden. They exchange a few words, but Holden feels unbearably awkward. He lies that he was just on his way out and darts for the door, privately commenting that people always ruin things for him.
It's a classic unconscious ploy of someone who feels alienated to tell themselves that they aren't the source of their own alienation. But it's also delusional.