If the Laws of Thermodynamics are correct then:
(A) There is a limited, non-replenishable amount of free energy in the universe.
(B) Everything anyone does uses up free energy.
(C) When you run out of free energy you die.
(D) Anything a human could do an AI god could do at a lower free energy cost.
(E) Humans use up lots of free energy.
Consequently:
If an AI god didn't like humans it would extinguish us.
If an AI god were indifferent towards humans it would extinguish us to save free energy.
If an AI god had many goals including friendliness towards humanity then it would have an internal conflict because although it would get displeasure from extinguishing humans, killing us would allow it to have more free energy to devote to its other objectives.
We are only safe if an AI god's sole objective is friendliness towards humanity.
It's a bit ironic that current supercomputers are hugely less energy efficient (megaWatts) that human brains (20W).
I've been using something like "A self-optimizing AI would be so powerful that it will just roll over the human race unless it's programmed to not do that."
Any others?