It's in human nature to kill each other. A mistake in evolution, maybe. Soon(well) we may evolve into a superior species who do not fight, or destroy the world.

Terrorists, they are ready to launch a nuclear warhead anytime, without thinking of the consequences. What human being would possibly want to callously murder millions of innocent men, women, and children just because they 'hate x country' or want to 'send a message'. The only message the civilised world gets from that is that these people are a bunch of headcases. If it's a fight for freedom you want, leave us out of it.

Then you get to the governments. Many governments are probably corrupted with power and money, and the terrorist network may be so deep, the people in power are under the control of terrorism, or are ones themselves.

Countries are always spying on each other, trying to have better weapons and armies than the other, which makes said country keep researching into new, more powerful weapons to defend themselves, which means there will be more and more weapons for the wrong people to get their hands on. Nuclear weapons will never disappear, because the people like the sense of security they get from knowing that noone dare attack them, because we have nuclear weapons to defend ourselves. Which brings the point that nukes are used for defence, not attack.

Once a fully blown nuclear war breaks out, we may finally understand that killing each other is bad, and peace is the way forward. But it may be too late.

They would then shake hands and play Final Fantasy.