What characteristics of the upper class have been highlighted in "The Garden Party?"

Mansfield's emphasis on upper class self-indulgence is one of the dominant characteristics in "The Garden Party."

The opening paragraph talks about how the weather could not have been better "if they had ordered it."  Such a reference shows the upper class sentiments of the Sheridans. They believe that even the weather should conform to their desire to host the party.  The discussions that take place that morning are centered on placement of ornaments and arrangements...

Mansfield's emphasis on upper class self-indulgence is one of the dominant characteristics in "The Garden Party."

The opening paragraph talks about how the weather could not have been better "if they had ordered it."  Such a reference shows the upper class sentiments of the Sheridans. They believe that even the weather should conform to their desire to host the party.  The discussions that take place that morning are centered on placement of ornaments and arrangements for the party. Mansfield writes these exchanges with with a tone that underscores their importance for the Sheridans.  It is as if the entire weight of the universe is brought to bear regarding the arrangements for their celebration.

Such a tone is enhanced with news of the dead worker. Laura insists that the party has to be cancelled, something that her sister cannot fathom: "... Jose was still more amazed. 'Stop the garden-party? My dear Laura, don't be so absurd. Of course we can't do anything of the kind. Nobody expects us to. Don't be so extravagant."  Jose represents the upper class sensibility that places primacy on her wishes over anything else.  Even though Laura suggests that the dead man casts a pall over the party, Jose and, later, her mother conclude that nothing should get in the way of their celebration. Jose further this by telling Laura that she cannot "bring a drunken workman back to life by being sentimental."  Mansfield shows the wealthy's view the poor.  Jose sees the deceased as a "drunken workman." Reflective of the upper class, she refuses to see someone who is poor as capable of being anything more.  As a result, the celebration should not stop. Laura's mother is more direct in her view of the poor:

People like that don't expect sacrifices from us. And it's not very sympathetic to spoil everybody's enjoyment as you're doing now.

The upper class are shown to be self-indulgent in "The Garden Party." They get what they want at the cost of everything and everyone else.