What does the vicious mother-in-law who goes out to sweep the floor at the door every morning mean?

Dissatisfied with you or showing off your labor.

1, dissatisfied with you: What did you do to make this mother-in-law dissatisfied? Sweeping the floor is an indirect way to express dissatisfaction, reminding you to pay attention to your words and deeds.

2. Show your labor: The elderly are used to cleaning every day and cleaning the environment at home and at the door. This mother-in-law wants to show her industrious side.