From Crazy or Disciplined? at Scott Adams's blog; he's the author of the Dilbert comic strip:
A Muslim, a Christian, and a crazy guy walk into a room. The one thing you can know for sure is that at least two out of three of them organize their lives around things that aren't real. And that's the best case scenario. ...
The best you can hope for in this life is that your delusions are benign and your compulsions have utility.
It's a worthwhile read.