In the novel To Kill a Mockingbird, why did Calpurnia fuss over the children so much before taking them to First Purchase African M. E. Church?

In Chapter 12, Atticus has to travel to Birmingham for an emergency legislature session. Calpurnia is left to take care of Jem and Scout and wonders what she is going to do with them on Sunday. After Scout mentions that Atticus left them money for the church's collection plate, Cal narrows her eyes because she remembers the last time Scout and Jem went to church without Atticus. Scout recalls the time when they tied up Eunice Ann Simpson and left her downstairs near the furnace. The entire congregation could hear Eunice banging against the radiator pipes which caused quite the disruption during the service. Calpurnia suggests they come to her church on Sunday, and the children are excited to visit First Purchase M.E. On Saturday night, Scout mentions that Cal roughly bathes her, and makes her soap all over twice! She even "invades Jem's privacy" to make sure he is taking a bath. On Sunday morning, Calpurnia puts extra starch in Scout's dress and makes sure her shoes are so shiny that Cal can see her face in them. Jem mentions that it is like they are going to Mardi Gras, and Cal says, "I don't want anybody sayin' I don't look after my children." (Lee 157) Calpurnia clearly takes pride in her job and wants the children to look respectable in front of her community members. She doesn't want her neighbors thinking she is not a hard worker.