Are good teachers born or developed?

Good teachers are developed not born. 

Temperements are intrinsic; sanguines, cholerics, melancholics, and phlegmatics are born (or at least fashioned in early childhood (or at the very least adolescence)).  Character, on the other hand is developed and certainly,'good' implies quality of character more than quality of temperament.  Sure, there are predominating, superficial preconceptions about what a good teacher is or isn't.  However, that facade changes from culture to culture (even from person to person).  The Greeks exalted symmetry but existentialists the absurd--it's cultural.

I used to think that a good teacher was outgoing, gentle, savvy, quirky, and somehow dominating--a Willy Wonka of sorts.  I used to think that until I tried teaching.  I was good at being a 'Wonka', in fact I think I have a natural disposition towards that; I'm a performer at heart.  As the quarter progressed, it was evident that the quality of my temperemant (the things I was born with) couldn't carry the class.  I would day-dream, then, about being a Clint Eastwood or maybe an Atticus Finch.  "If only I were calm, cool, reserved...", I thought.

But 'good' has nothing to do with that.  Caring, committed, knowledgeable, faithful: these are 'good'.  And you don't get them by nature.  It has nothing to do with temperament.  They are developed like muscle.  You have to work them out daily.  It's a blood, sweat, and tears kind of thing. 
With regard to being a good teacher: I don't ask myself I am (intrinsically), but rather, if I am willing.

The role of a, Teaching Artist.

To me, education facilitation feels no different than composing or performing a song.

It's not work.
It isn't void of passion.
It doesn't come easy for it to flow naturally.
It's heartfelt and heart-centered.
I always receive more in return than what I share.

I don't care what anyone says, education is an art.