Now, I know that the title is incredibly vague. This covers my views on three topics, robotic destruction of the world, cybernetics (define it as you wish, here used to describe unnecesary body part replacement), and pollution/environmental damage/radiation.
We will kill ourselves to go to the next level of scientific progress. And we won't shed a tear about it either. We'll be too oblivious until the world comes to an end.
First, robots are a major threat. We can build robots, we can make them assigned to do certain jobs. We can't make them able to hurt humans, or even wield weapons. This is because with the first self-aware robot we make, or shortly after, we will have signed our own death warrants. Logically, as a species, robots have no reason why not to kill us.
Second, cybernetics are a major risk to our society. I would personally trade both my arms and both my legs out for a powerful mechanical replacement if the tech was good enough, but, the problem with that is the unknown psychological damage (and worse, the known psychological damage) of rejecting one's own humanity for a few more ounces of power.
Third, we risk wiping ourselves out with pollution, environmental damage, and radiation. We don't care about what happens to our unconceived descendants, because, quite frankly, we can keep on living happily as we turn our air green with poison, kill our plants that give us air, and dose ourselves with as many gamma rays as we can count.
Granted, the world will end within a couple millenea at most, if the events of the Bible come true, but that does not mean that we have any excuse to continue down this path of technological self-destruction.