Like all great advancements in technology, nanotechnology will eventually kill us all.
We’ll have vessel-repairing robots in our bloodstream, and drug-delivering bots in our synapses. Before long, we’ll be little more than fleshy carriers of nano-ecosystems. Actually, we’re already that for the bacteria in our gut, so maybe it won’t be so bad after all. Unless the nanobots and the bacteria have a war or something. That would suck.