Final answer:
Nonporous flooring is a bad choice for dining rooms and public restrooms due to its tendency to stain, become slippery when wet, and lack aesthetic appeal.
Step-by-step explanation:
Nonporous flooring is a bad choice for dining rooms and public restrooms because it is prone to staining and can easily become dirty in these high-usage areas. Additionally, nonporous flooring like polished tile or concrete can be slippery when wet, increasing the risk of accidents. Lastly, nonporous flooring may lack aesthetic appeal compared to other flooring options like wood or carpet.