The two examples I can think of atm are in “Cash for Gold” when Cartman is trying to buy jewelery from the asian jeweler and he picks up that the workers there are patronizing him.

The other is in “Informative Murder Porn” when the boys go to the Minecraft kids house and after they close the door the first time Cartman tells the group something is funny because the kid said the exact sort of things Cartman says he would have.

Any other moments like this?