Spite is a malicious desire to harm, annoy, frustrate, or humiliate another person, often one who has no animosity towards you or you them. The reason why spite is instinctual is that a good defense is the best offense; if another member of your tribe is ascending the social hierarchy, with all that entails including mating opportunities, it's in an individual's best interest to hinder that. This is simple politics, and the favorable interpretation of spite; the reality of spite is much less utilitarian because it's normally a response to envy, jealousy, or resentment, and has no positive reward other than secret satisfaction. Sometimes people act spiteful because of the feeling of control it gives, which they savor by knowing it was them who tipped the balance, and control not acted upon is an opportunity lost. Even if there is no outward personal gain, the dopamine hit of being spiteful is enough. Because spite is a control issue, it doesn't have to be intended against another person
