In supermarkets, shops, regardless of what is offered in them, there can always be questions related to the proposed assortment.
From how competently you will talk with the seller, it depends on how much and the quality of information will be received about the offered product or the offered service.
Competently posed question. We must always understand that a specific question implies a specific answer. But in order to be able to ask such a question, you may need to study at least the basics of information about the proposed product or service. This will allow not only to correctly orient yourself in the offered assortment, but also, if necessary, will allow the seller to answer the questions posed to him more competently.
Politeness. If you talk to Seller Politely, not as a servant, but as an equalPerson, the seller will treat the buyer with respect and understanding, and, in which case, will be able to select from the range of goods or services exactly what you need.