Sissy jupe doesnt greet mrs sparsit at mr bounderby`s house?why?does she hate her or what?

It seems reasonable to assume that Sissy does not greet Mrs. Sparsit because Sissy is a force for good and knows that Mrs. Sparsit aspires above her station. Mrs. Sparsit is not honest and wishes to marry Bounderby, thus causing problems in the household.