What would be a good theme to analyze from "Miss Brill"?

Katherine Mansfield's short story "Miss Brill" is a
depiction of life for an older woman named, not surprisingly, Miss Brill.  One key theme
in this story is that of isolation.  She is a quaint creature who has a weekly routine
which she follows religiously.  Each Sunday, she releases her rather shabby ermine fur
from its box (playfully teasing it) and heads for the park.  She is as prim and proper
and precise as her name, and the fact that she's a spinster is no surprise to us as we
follow her this Sunday.  At the park, she is lost in the drama of those around her as
she sits on the bench.  She is struck with the sudden thought that the events which
unfold before her each week--the music, the couples, the varied activities and
relationships which she sees--are a play, and she is the
audience. 

This is a clear picture of isolation, of being
on the outside looking in.  She is alone and isolated in a way which she is clearly
unaware but is nonetheless tragic to see.  Miss Brill is content to be on the
outside--until the arrival of a young couple who sit on her bench.  They are being
playful and a bit romantic, until the girl says she can't do this with such a ridiculous
old thing sitting right there.  After she overhears this hurtful comment, Miss Brill is
faced with the knowledge that she is actually just one more tragic character in this
"play" of life, not the carefree audience member she saw herself as being.  She doesn't
say so, but she understands that she is one of the lonely
actors. 

Being part of this show does not mean she is no
longer isolated; instead, it means she now recognizes her tragic
isolation in a way she never did before.  Her time of blissful ignorance is over.  She
follows her usual routine on the way home, but it is a joyless journey.  She stops at
the bakery, where the small delight of an almond on her pastry once gave her joy, but no
longer.  She arrives at the house and puts her ermine torque back in the box, and she
hears it crying.  What she hears, of course, is the sound of her own tears.  The visual
of being returned to a box, of coming back home to her "cupboard," highlights her
isolation from the joys and delights of the world.  Miss Brill's eyes have been opened
to her own isolation and she weeps.

I've added an excellent
e-notes link below for even more ideas.