Recently, I have been studying the Myers-Briggs system of personality classification, which is based on the ideas of Karl Jung.  For short, it is often referred to as the "MBTI," or Myers-Briggs Type Indicator.  I found this system to be interesting, but woefully incomplete.  In the interests of making the MBTI a truly useful tool, I have undertaken to remedy its flaws.  The results follow.  (But if you want to be stuffy and read about the real deal instead, see, for example, www.keirsey.com.)
    First, a summary of the old, defective MBTI.  The MBTI consists of four categories or "dimensions," each defined by a pair of types.  They are:

1.  Extroverted (E) / Introverted (I) - I think most people have a pretty fair grasp of this.  It's kind of the difference between a quasar and a black hole.

2.  Intuitive (N) / Sensing (S) - This has to do with how you take information in.

3.  Thinking (T) / Feeling (F) - This has to do with how you make decisions.

4.  Judging (J) (or scheduled) / Perceiving or Probing (P) - This has to do with how you organize (or fail to organize) your life.

    Note that each is represented by a letter.  Usually, it is the first letter of the type.  However, since Jung wasn't clever enough to think up types with all unique initials, we are stuck with "N" for "Intuition."  This may at first seem confusing.  However, if you are an intuitive type to begin with, it will probably come to you.  Anyway, your personality type is represented by a combination of the letters.  For example, "ESFP" (like my son) or "INFJ" (like my daughter).  I have to admit that this initials thing was a master stroke.  If we had to remember something like "Extroverted, Sensing, Feeling, Perceiving," no one would ever use this system.
    If you're one of those thinking types, you have probably figured out that there are 16 types in all.  If you're a feeling type, well, just trust me.  Now, here's a critical point:  With some 5 to 6 billion people in the world, 16 types doesn't seem hardly enough, does it?
    We will return to the previous point in a moment, but there's one other thing I need to explain first.  How the heck do you know what type you are?  Astrological charts?  Transcendental meditation?  Osmosis?  No, no.  It's very simple, really.  You just take a little test consisting of either/or choices.  When the results are totted up, voila!  You have your type.  I will give some examples shortly.  (But if you really want to take a test prepared by a so-called professional, you can check out that other web site, www.keirsey.com, among others.)
    But enough prelude.  I ask again:  Do you really think 16 types are enough?  I can tell you that I have observed way more than that.  I have added a third set of types, giving a total of ...  Well, I'm not a thinking type, so figure it out for yourself.  But it's a lot more than 16!  So, without further ado, here are my modest improvements to the MBTI:

1.  Extroverted (E) / Introverted (I) / Buttheaded (B)  (Note:  "Perverted" is being considered for a future upgrade, but I haven't thought up any other "fourths" yet.)

Extroverted: Outward directed orientation toward the world
Introverted:  Inward directed orientation toward the world
Buttheaded:  World is oriented toward oneself

2.  Intuitive (N) / Sensing (S) / Making it up as you go along (K) - See how I finessed the problem of having two types with the same initial?  Huh?  I'm following precedent here!

Intuitive:  Receives information intuitively
Sensing:   Receives information by observation
Making it up as you go along:  Doesn't receive information

3.  Thinking (T) / Feeling (F) / Managerial (M)

Thinking:   Acts more on thoughts
Feeling:     Acts more on feelings
Managerial:  Unthinking and unfeeling

4.  Judging (J) (or scheduled) / Perceiving or Probing (P) / Anal (A)

Judging:      Prefers to have things nailed down
Perceiving:  Prefers to keep options open
Anal:  Prefers to have things, and especially people, trussed up

Sample questions

1.  When you are among strangers, you tend to
    a.  Chat them all up a treat.
    b.  Hold them at bay using religious artifacts, rude noises, and poor personal hygiene.
    c.  Tell them about your latest operation, show them slides from your vacation to Sheboygan, and make them clean out your utility shed.

2.  You believe that
    a.  Facts speak for themselves.
    b.  Facts need an attorney to speak for them.
    c.  Facts are purely optional.

3.  If you have to give someone bad news, you
    a.  Tell them straight out.
    b.  Try to find someone else to do it.
    c.  Really love it.

4.  When working on a project, you prefer to
    a.  Have everything scheduled and work to deadlines.
    b.  Just let it happen in between golf and squash.
    c.  Create arcane processes, require mounds of documentation, and revel in the screams of your co-workers.

There.  Now, isn't that better?

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A small postscript.  Your humble writer and would-be psychologist has been diagnosed as a terminal INFP.  Old system, that is.