What difference? ('Are you finished' vs 'Have you finished')

'Have is more polite, are implies some impatience to me.

Hello Taka

1. 'Have you finished?' could be said in any situation:

a) Mother to child eating soup: 'have you finished?'
b) Teacher to student during test: 'have you finished?'
c) Male to female who has been complaining bitterly about the ring of shaving
foam and stubble round the bathroom sink: 'have you finished?'

2. 'Are you finished?', as Nona says, would mostly be said in situations like 1c,
and implies a certain degree of impatience (or mock-impatience):

a) Female to male who has been explaining the workings of the internal
combustion engine for the last half-hour: 'are you finished?'

b) Male to female who has been shouting abuse and at last collapses
sobbing into an armchair with her hands over her face: 'are you
finished?'

(Reverse 'male' and 'female' for less stereotypical scenarios in the last 3
examples.)

It's difficult to pinpoint exactly why 'are you finished?' is so derogatory. We say
'is it finished?' of films, plays, tv programmes; perhaps the speaker is
implicitly likening the other person to a mechanical recording.

MrP

Hmm. Now you mention it, CJ, trying out the two phrases
in different accents does give different results.

I think my last post needs a question mark above it, pending
more field research...

MrP

Thank you, people, but what I'm interested in is not which usage for which situation, but why such difference in nuance between "are finished" and "have finished". Any idea?