Compare colonel Pickering and professor Higgins in Pygmalion by G. B. Shaw.

You
already have a very thorough discussion of these two characters in .  I
would simply add a couple of things. Pickeringis, indeed, a rather harmless foil to Higgins, and
he is the one who treats Liza with respect and dignity.  She is quite clear as she talks to the
Colonel in Act V--she is appreciative of his help and recognizes he would have done the same
with anyone because that's just who he is.  On the other side of that, though, he certainly
could have limited Higgins's bullying and nagging.  Instead, he benignly watches the process and
doesn't intervene much at all.  It's true that Liza was not in mortal danger, of course, but he
certainly could have been more involved and shown more compassion.  It works out, though, and
Liza is grateful.  She says to him: 

You see, really and
truly, apart from the things anyone can pick up (the dressing and the proper way of speaking,
and so on), the difference between a lady and a flower girl is not how she behaves, but how
she's treated. I shall always be a flower girl to Professor Higgins, because he always treats me
as a flower girl, and always will; but I know I can be a lady to you, because you always treat
me as a lady, and always will.

Higgins is a bully, but he
got the job done.  He does so rather heartlessly, treating Liza as an experiment rather than a
fellow human being.  In fact, when she points that out to him, Higgins proudly proclaims that he
treats everyone that way--king or peasant is all the same to him.  This is his flaw, of course;
people don't really matter except how they fit into his plans.  (Just ask his mother--she would
agree.) 

Perhaps it is true that these two men are two sides of a coin or two
parts of a whole.  If so, they can both take credit for the accomplishment of turning Liza into
a "lady."  But only one of them does, of course, and that's
Higgins.