Well I do not know if bad things happen for a reason although one day I did come up with a theory. Bad things are important, think about it if there was no such thing as a bad deed then there would be no bad people. Everyone would be the same, evil people would be the same as good. Now for the sake of argument lets just say there is a hell. How would we distinguish who should go there, who should be punished. Also if there were no bad things then there would be no good things. So I do not know if they have a reason but they kind of have a purpose. Especially if you believe in heaven and hell(or some form of it). "it is good that war is terrible otherwise we might become accustomed to it" Argh I forget his name.