Sigmund Freud compared the human mind to an iceberg, where the tip above water represents consciousness and the region below water symbolizes the unconscious mind. Freud described three basic personality structures: the id, which seeks pleasure and operates unconsciously; the ego, which mediates between the id and reality; and the superego, which acts as the conscience. The id and superego are in constant conflict, as the drive tells us to do one thing while society tells us to do something else.