Do you ever worry that robots or AI will become so powerful one day that they will destroy humans? Or does that only happen in movies?

Definatley. The scary thought is when AI can "reproduce" so to speak but on a subatomic level. Microscopic robots that have the potential to wipe out humanity with no way of stopping them. (Movie idea).

Also robot terrorism, that might be a thing one day too.

Not worried, but absolutely yes. There is no such friendly entity as 'humanity', not on this planet yet anyway.

As long as different blocs are building weapons against each other, it is only a matter of time that robots will be, not turning on 'humanity', but deliberately designed to attack humanity from one side or the other, and perhaps even to repair and replicate themselves.

Not the fault of the robots, but the inability of divided humanity to reconcile our so-called 'human' differences.

No. Humans are doing a 'good' enough job of destroying our species without any help. Though perhaps AI could hurry it along a bit, and in doing so, save the planet and all the other species.

Sure. Robots are already being made for war. One goes awry and kills a whole bunch of innocent people and the manufacturer will say "that wasn't us, that was our algorithm."

The only question is will we be killed by Google killer bots or Apple killer bots?

I don't think they will destroy our life, unless we demand anything entirely for them. The robot or AI is just a tool which improves our daily life. Robot or AI should not take over our jobs completely because working hard for them improves our creativity and humanity, so our life will be improved more if we combine our good point with theirs. Therefore, we need live together controling robot or AI.

If they are the robots you find in Japan, will never be worried about Peppers or hotel desk clerk robots taking over the country or killing off humans. More worried from the human robots I see day in and day out.

Now Maria's idea above is good.

If we could just create robots that would intervene and stop humans killing each other... and remind us of our higher nature or face instant justice, etc.