There are many potential problems with the singularity. For one thing, the concentration of wealth into the hands of a few individuals is dangerous, because it would give them power over the rest of the world's humans, making it very easy for them to abuse their power, and because it could potentially plunge most of the world into poverty.

The singularity is also dangereous because, as I mention on the What is the singularity? portion of this site, human effort and labor could become unnecessary. Human beings would have, literally, no purpose. This is most certainly a social crisis; we would have to redefine what it means to attempt to live a meaningful life. It is as Bill Joy points out in, "Why the future doesn't need us": perhaps we would adjust, but do we really even want to do that?

Then again, the robots might just blow us up and save us the trouble of caring.