What Makes People Tick?

ISIS, Hamas, Al-Qaeda, the Taliban, Hezbollah, Islamic Jihad, the Muslim Brotherhood, Boko Haram, the al-Nusra front... No doubt there are groups just as bloodthirsty that are not on this list because I can't think of them off the top of my head. These are all names of organisations I wish I'd never heard of. Because these names belong to terrorist groups that seem to find it necessary to kill, hurt, harm and maim; to execute people, to enslave and rape women, to terrorise and kill and cause destruction in an effort to further their own cause.  The cause they are attempting to further (to impose / to enforce) is Islam. Or rather - their own radical and violent interpretation of Islam with current actions seemingly geared entirely toward the spread of (their version of) Islam through any means. While I am a student of the world's peoples and religions and consider myself someone who attempts to walk in another's shoes to understand them and learn what it'...