An Odd Thought, Maybe?

My mind tends to jump randomly from thought to thought. I can't seem to control it. When I see, hear or read something my thoughts take flight. At times I allow them to take that flight and ignore them. Gone and forgotten (hopefully but doubtful). Other times I grab them and attempt to ground them. After what happened at the Boston Marathon one thought I have managed to ground is, why? I can't seem to lose it. Why would someone do tha?. I'm sure it's a question I will never get a definitive answer to along with why we lost the twin towers. I do, however, find comfort in the fact that most United States citizens would rather give their lives in order to preserve life rather than giving away their own in order to take away anothers.