Sigmund Freud said that hatred was a selfish feeling that wishes to get rid of whatever is making that person unhappy. The Penguin Dictionary of Psychology says that hate is a "deep, enduring (long-lasting), intense emotion expressing animosity, anger, and hostility towards a person, group, or object."
Hatred can often cause the hate crime and International Covenant on Civil and Political Rights prohibits inciting hatred by the Article 20.
Hatred Facts for Kids. Kiddle Encyclopedia.