What is funny about the dinner sccene with the children?

The Pockets’ home is a bustling, chaotic place where the servants run the show. Matthew is absentminded but kind, and his wife is socially ambitious but not well born; the children are being raised by the nurse. Pip’s fellow students are a strange pair: Bentley Drummle, a future baronet, is oafish and unpleasant, and a young man named Startop is soft and delicate. At dinner, Pip concentrates on his table manners and observes the peculiarities of the Pockets’ social lives.