The why?

We all remember  the plotted plane bombing on Christmas day. We all remember how we would of felt if it would have been accomplished. But i think the question that kills us all in the inside is that why? Why would someone to do something so cruel. Why would someone be so mean to all of these people. Who gives them the mindset that doing something like this is maybe good? These questions of why can never been answered, unless somehow we can get into these peoples minds and see what they are thinking, but sadly we will never no for sure.