Beware the angry man.
Every newspaper has correspondents who are perpetually angry. I'm not talking about the righteous indignation that any citizen can feel when confronted with an issue that requires fire in the belly.
Anger spurs action. It's a good thing. I'm talking about people who are angry all the time. They are invariably men. There is frequently a bitter underlying cause. In my experience, they have come out on the losing side of a child custody issue. Some have mental health issues, or deeply closeted sexual identity issues.
Some see themselves as champions against injustices. They fixate on extreme causes, or latch on to any cause. Some become serial litigants in court, arguing over minutiae. They won't take no for an answer. Some run for local government (thankfully, always unsuccessfully). This is a generalisation, formed from my experiences as a reporter and editor.
People such as these sadden and scare me, because often they actually have a point. But something has clearly derailed in their lives. Their anger needs an outlet, to the point when any action against the system becomes righteous. I believe this is what it takes to become a bomber.