5 ideas
Giton has a fresh complexion, a firm step, and a loud laugh. He interrupts, spits freely, and is thought witty and wise. Phédon is thin and hollow-eyed, speaks low and briefly, apologizes, and stands aside in doorways. Each portrait ends with its cause, 'He is rich' and 'He is poor', showing that behavior read as personality is produced by money.
Onuphre, the false devotee, avoids the showy piety of the stage hypocrite. He only arranges to be seen at the right moments, and he chases inheritances that no one could openly reproach. Accomplished hypocrisy copies the modesty of real virtue, so the absence of display is no proof of sincerity.
The man who knows the court controls his gestures, eyes, and face. He is deep and impenetrable, hides injuries, smiles at enemies, and gives no outward sign of his real feelings.
La Bruyère describes 'certain wild animals', blackened and burned by the sun, bent over the soil, and then reveals that they are human beings, the peasants who feed everyone else. The deliberate shock exposes how the polish and leisure of court society depend on people it does not count as fully human.
The verdict on vanity or ambition comes afterward. Vice shows up most reliably in small, repeated social habits, so exact observation of conduct is a better guide to character than anything people say about themselves.