Harry's Politeness & JKR's Diction

[Megan]

No: HPFGUIDX 29365

When considering Harry's background (as a normal child) one has to
wonder where and why he always uses (for the most part, mind you)
extremely good manners.  He uses "please" and "thank you", addresses
adults using proper titles and last names (when he meets them
initially), inquires as to people's well-being, responds politely in
everyday conversation, etc.  OBVIOUSLY, this is discounting once he
becomes friends with people (don't we all stop being quite-so-polite?)
or in heated situations, but for the most part, Harry is a very
well-behaved polite young chap.

I know the Dursleys would only expect Harry to address them with
respoect (pre-wizardness, I suppose), but I would think this prolonged
agony of mistreatment would only turn Harry bitter and make him more
like Dudley in terms of politeness.  If you think, this is the ONLY
life he has known & most children raised in this manner turn out
disfunctional--at the very least someone quite disgruntled at being
FORCED to use the niceties of manner and language, so when put in a
situation where no one is EXPECTING him to be polite (no authority
figure there to punish him--the Dursleys) that they would rebel & be
the typical apathetic adolescent.

On the same lines but not quite, has anyone noticed how in GOF JKR
initially names Ludo Bagman "Bagman" and Barty Crouch "Mr. Crouch"? 
Is this distinction designed to subtly show the respective authority
of these two men?  It could be because Percy address Crouch as "Mr.
Crouch" initially, so this how Harry thinks of him & Mr. Weasley calls
Bagman "Bagman".  Along the lines of Harry's politness, the Weasley
parents are always named "Mr. Weasley" and "Mrs. Weasley" in every
book so far.  Just an interesting distinction between Bagman and Crouch.

-Megan (who thinks entirely too much)