...that some people fit neatly into a type and others don't?
For example, me and Herzy - according to the vast majority of anyone who has an opinion on socionics, I'm INFj and she's ESTp. We're even held up as representatives of our respective types. Then there're people like Implied, or Ezra, or your second cousin Margaret who defy attempts at pinning them down into one of the 16 set socionics types.
Why is that?