He that respects himself is safe from others; he wears a coat of mail that none can pierce.

Criticism, contempt and manipulation all work by finding the doubts a person already holds and pressing on them. Someone with a steady sense of their own worth offers fewer such openings, so insults land more lightly and flattery gets less purchase. The armour is not total, and nobody who has been harmed by others lacked self-respect; people get hurt regardless. What self-respect does provide is a place to stand while it happens.

Think of a remark that stung you recently. Ask which of your own doubts it touched. Tending that doubt directly, by examining the evidence for and against it, can do more than trying to avoid the people who poke it.