When does healthy scepticism curdle into delusional paranoia?

We all love conspiracy theories about events and people we are familiar with - assassination of famous politicians, wars, UFOs, NASA's lunar mission, etc. Why? What feeds our 'need' for such theories? How do we retain our sanity in spite of doubting almost everything we read, hear and watch (on TV)? This rather long piece contains some interesting points. Skim through it.

Keep this quote from the article in mind:

The astronomer Carl Sagan once famously said about UFO conspiracy, that it was fine to have an open mind, but if your mind was too open, then your brains fell out.