Anger does not make history. Power does. And power may be supplemented by anger, but it derives from more fundamental realities; geography, demographics, technology, and culture.
In a way, we can have a much easier discussion about the future of technology than we can about why a young man kills another man in a war.
There is a radical and unprecedented shift [in war] that is part of the general transformation of civilization. First, understand that the past 150 years of warfare are totally unprecedented in that we introduced a breathtakingly inefficient technology: guns. In the First World War, and this is not an exaggeration, it took 10,000 rounds of ammunition to kill one person. Any given shot had a one in 10,000 probability of ending someone's life.
