What does Mansfield want us to learn from Miss Brill's false perception of reality?

The theme of appearances and reality is of critical importance in "Miss Brill."  One thing that Mansfield seeks to create in the mind of the reader is the ability to perceive oneself and one's place in reality without a sense of deception.  Miss Brill is a character who engages in some level of self deception in her belief that the individuals in the park fit into some type of drama and that others represent a sense of dull banality.  She believes herself to be opposite of this, when in reality, she is a part of this monotony and embodies an existence that is replete with an inflated notion of self.  At some point, the reader is left imploring Miss Brill to actively interact with some aspect of her existence.  Human emotions and interaction cannot substitute for self delusion and the notion of self that is separated from an existence, regardless of how "boring" or "odd" that existence might be.  The fact that the conclusion of the story seems to have Miss Brill almost "blame" the stole for her condition indicates that she still might not have grasped the importance of authentically interacting with her environment.  Miss Brill's only interaction with this setting is to serve as the target of the couple who sit at the end of the bench.  It seems ironic that her only real connection to this world is one of scorn, ridicule, and rejection.  If there is a lesson in the short story, it would be that human connection is the only way one can effectively gauge their level of understanding of self and prevent a sense of appearance which is divergent from reality.