Everyone certainly has the capacity for rage, but some people are much quicker to it and it is much more explosive and deadly. The criminologist Lonnie Athens describes a step-by-step process of brutalization and humiliating provocation that leads to violent outbursts of rage; at the end stage, avenging even the most trivial acts of perceived disrespect. If you want to understand how people develop hair triggers and explode in deadly rage, read this very short book.
The psychologist Philip Greven describes how corporal punishment (which is often deeply humiliating to children) tends to produce bullying, scapegoating, domestic violence and apocalyptic rage in people subjected to it. This more or less explains the sort of background rage in a society, from the hatred of blacks and illegal immigrants, to the more amorphous free-floating anger of the birthers and the teabaggers. It also explains the fire and brimstone wrath of religious types and their furnace-like hatreds of people unlike themselves.
And this even applies on an international scale, such as when the British, at the height of their empire, made people feel like second class citizens in their own country—sort of how we are doing in Afghanistan and Iraq. People develop deep wells of rage in response tend to be people who have been seriously humiliated so if you want to really understand terrorism and terrorists, you need only look at the humiliations they have suffered at the hands of an oppressive power. This applies to the British in Northern Ireland, the Basques in Spain, the Algerians in France, and the Muslims whom we have tortured for years on end and then wonder why they hate us.
I have never even come close to losing my temper my whole life until a few years back when I got sent to prison on a drug charge. There, the guards think they have a license to humiliate you; and I must say, that it is a good thing they don’t let prisoners have anything sharp or I would have come very close to stabbing one of these motherfuckers in the neck. I never had a well of anger before, but I do now. It has taken years for it to subside to the extent it has, and it is still something I have to work on.
So, no, it isn’t genetic; nor does is spring from some well of incomprehensible evil. I’ve known literally hundreds of angry men teetering on the edge of violence, and every single one of them has been seriously humiliated, screwed over and betrayed in some fundamental way. If you ever wondered why gangsta rap is so all-fired angry, you should see the absolutely horrible and blatantly discriminatory way that blacks are treated in prison.