Hate is the emotion involving severe abhorrence and detestation being felt and/or directed towards another person, animal, location, object or situation. It has many causes, most of which involve the feeler perceiving a wrongful act being committed against him, and in turn feels a desire to extract revenge or to assert his or her authority. The condition of feeling hate is known as hatred.
In extreme cases, hatred can lead to rage or irrationality. Often these will develop if hate is not dealt with for extended periods of time, or if the initial cause is very severe. In these cases the emotion can be expressed in the form of physical or verbal abuse. Lesser forms of hatred can lead to the breakdown of relationships and the social shunning of a person.
Historical Views of Hate
The Reverend Dr. Martin Luther King, Jr. once said, "like an unchecked cancer, hate corrodes the personality and eats away its vital unity. Hate destroys a man's sense of values and his objectivity. It causes him to describe the beautiful as ugly and the ugly as beautiful, and to confuse the true with the false and the false with the true."
Historically, others have defended hate as a valid expression of one's feelings or as a tool inspire the defense of a way of life. Rev. Jeremiah Wright, for example, sees hate as a potential source of good in that it can inspire communities to better themselves at the expense of their oppressors.
... we always want others to love us. Someone thinks, "My mother hates me, my sister hates me, my uncle even hates me.. But that person looks so cold and hateful, no wonder no one loves him!" Thus you transfer such treatment to others, even to dogs sometimes! You might kick a dog who is minding his own business, because you have no other place to relieve your stress. Or you might go and poke a cow who is just eating grass, or even call names at the birds who are flying by. You might hate to see a couple of birds getting along so well together when you are so miserable. - Rev. Sun Myung Moon, In Yun and Encounter 
The Seven Deadly Sins
The Seven Deadly Sins may be categorized in three groups (see, for example, Dante's Purgatorio). Hatred is from the first group:
- Pride, envy, anger and hatred are sins resulting from excessive self-interest. According to Ayurvedic medicine they result from Pitta (Fire and Water element) dosha disturbance in the mind/body.
- Seven Deadly Sins
- Afflictive emotion
- Three poisons (Greed-Lust of Vata, Anger-Hatred of Pitta, Ignorance of Kapha)
- Pitta (Fire and Water element) Dosha in Ayurvedic medicine
- Romantic paintings