If you are shy and have a hard time talking to others, people might wrongly interpret your quietness as haughtiness. Haughtiness is thinking a lot of yourself and not much of others.
The word haughtiness originally comes from the Old French adjective haut meaning "high" and later developed to mean having a high estimation of yourself. When you think of the word, imagine a Queen riding by on a horse, chin upturned, not paying any mind to her subjects below. Her Highness might as well be called Her Haughtiness up there.