Based on the short story "A Rose For Emily," Faulkner shows a use of modernism by deviating from the norms or expectations of the time in which it was written in 1930.
One example of Miss Emily's deviation form the norm of her society would have been riding out with Homer Baron, someone who would have been considered beneath her socially. I would not expect someone from her social status to spend time with someone who is not her equal.
A second example of Miss Emily's departure from the Southern norm would have been her trip to the druggist to buy rat poison. I would have expected Tobe, her manservant, to do this, not Miss Emily herself.
A third example where Miss Emily is something of a surprise is because she lives alone. A woman of the South would either have married or had a female relative come to live with her. Miss Emily does not marry (mostly because her father is so picky about who she sees), and she does not call back her female relatives when she and Homer Baron do not marry.
The most startling departure Miss Emily's character makes is not only murdering Homer Baron, but continually sleeping with his dead corpse even many years after his death. Faulkner would have surprised his readers most with these final details in the story.