Humiliation need not involve another person; it can be a recognition of one's own standing, and can be a way of casting away false pride.
Humiliation of one person by another is often used as a way of asserting power over others, and is a common form of oppression or abuse. Many punishments are deliberately designed to be humiliating, e.g. tarring and feathering, pillory, mark of infamy (stigma).
However, some people find humiliation by others erotic in certain circumstances: see erotic humiliation.