Final answer:
A customer might consider a store unsanitary if they observe poor hygiene practices, signs of pests, or expired/spoiled food.
Step-by-step explanation:
A customer might think a store is unsanitary for several reasons. One reason is if they observe poor hygiene practices, such as employees not wearing gloves or hairnets, or if they see dirty countertops or utensils. Another reason could be if there are visible signs of pests, such as mice or cockroaches, in the store. Additionally, if a customer notices a bad odor or sees expired or spoiled food on the shelves, they may perceive the store as unsanitary.