The answer to 'why is my countertop stained' is that countertops can become stained for a variety of reasons, such as spills, buildup of grime, or exposure to acidic substances. Common causes include food and drink spills, makeup, nail polish, and cleaning products that are too harsh for the countertop material.
Stains on countertops can be frustrating, but there are often DIY solutions that can help remove them. For light stains, you may be able to clean the surface with a mild soap and water or a specialized countertop cleaner. For tougher stains, you may need to use a paste made from baking soda and water, or a commercial stain remover. If the stain persists, it's best to call in a professional cleaning service to evaluate the issue and determine the best course of action.