Terror trouble

I don't understand terrorists. I don't understand what drives them to mass murder people. Its not as if they are crazy, insane people. Perfectly sane, well educated people develop bombs designed to cause maximum damage. Robbers, murderers, assasinators harm people because they are directly blocking the way to their target. But how can arbitrarily bombing any market place or hospital achieve anything? People get scared, governments shaken but I doubt if the terrorists get anything other than scaring people. Governments don't fall on their knees begging them to stop. If at all it hardens people against them and worsens the divide. If an educated person decides to bomb a busy street full of nameless, faceless people he had never before seen in his life, its a mockery of the education he received. Education isn't just about becoming the best professional but more importantly about becoming a good person.