Shootings; Why?

I don't understand how anyone could ever bring a gun or any other weapon to school and kill anyone, especially innocent people that you don't even know. I know they must be psychotic but I don't know why they would do such a thing despite their mental capacity. VT, NIU, and even columbine have been some of the worst school shootings in the U.S., if not the rest of the world. Is there enough security? Well, I don't think that any amount of security will ever make any place safe from desperate and stubborn people. We can do everything that is humanly possible to prevent these kinds of things, but you know what, they will still happen. Unfortunately the world is designed to keep producing these insane people and for some reason they are able to get their hands on weapons and use them to take innocent people's lives. Will there ever be any where you can go and not be around violence? School should be one of those places, free of fear and free of violence. Your only worries should be homework and finals. All I'm saying is that our society needs some reformation and something needs to be done.