Since the sudden appearance of a certain dysfunctional personality [soon to be ammended I'm sure] I thought I'd do a search to get behind the mindset of such a person,and why they do the things they do.
I won't bore you with the search results,but I did come across this free Jung Topology personality test in my travels,took the test and it seems a fair appraisal.

It sorts you into one of four personality types,and within another four within that type.

What are you?

A Guardian,Idealist,Artisan or Rational.

http://www.humanmetrics.com/cgi-win/JTypes1.htm

I got Rational-Mastermind.