A lot of things. Our failure of mental healthcare, the breakdown of real life connections, the general feeling of hopelessness, and frustration felt by many across the nation, the failure of proper reporting, and investigating beforehand, and the glorification of these disgusting acts of violence by today's media.
I hate it, too. Things didn't use to be like this, and it pisses me off to no end that shit like this is now common place in America. Unfortunately, until both sides stop pointing the finger at each other, and actually decide to come together to solve these problems, tragedies like this are going to continue to happen, and all we can do is just protect ourselves the best we can. Which sadly means having to go to church armed, because some degenerate lunatic might decide to shoot it up.