What are you talking about? Many refund agreements have exactly this in mind. It's a competitive advantage for the store to be lenient.
When I worked at Walmart and Target during summers as a teen, we were encouraged to get the customer to buy a few different options (curtains for example) and tell them to just return the ones they don't want. Especially clothes.
I encourage you to check out the terms of refund for the places you shop instead of assuming you're stuck with a product you don't want.