Humiliation is literally the act of being made humble, or reduced in standing or prestige. However, the term has much in common with the emotion of shame. Humiliation is not in general a pleasant experience, as it reduces the ego.
Humiliation of others
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. However, it can also be consensual, as part of an agreement with a lover of sexual humiliation. In either of these cases, it may be motivated by sadism. In addition, many punishments are deliberately designed to be humiliating, e.g. tarring and feathering, pillory, mark of infamy (stigma).