How pissed do you have to be

This just in: A man on a bus in Canada, stabbed and cut the head off a fellow passenger. Across the world another man, decapitates his girlfriend, parades the head through town, throws it at police and runs over two doctors as he is trying to get away. Did I mention, the police accidentally shot a bystander trying to catch this guy? I guess I have never hated a person enough to want to make their head disappear. What kinds of weapons do these guys carry around. An axe would be noticeable and maybe give the intended victims a heads up (pun intended) and a knife would take a while and if your that pissy you are short on the patience that's needed for job like that. Just a thought.