In order for a person to want to buy from you, in most cases you will have to get to know that person and develop a bond with them. This requires you to be personable and ask questions, but most importantly you have to remember that person. Service after the sale is a very important and in order for someone to want to continually do business with you, whether it is a service or a tangible item, you will want to remember them, so they feel important to you.
My dad sells insurance and has for thirty years, and it amazes me that he can remember all of his clients especially since he has so many. I think that in order for a businessperson to be successful, you have to take the time to make the relationship go past just a client/customer relationship. If you remember things about them, they will find you more trustworthy and you will keep if not further the trust that you established after the initial sale.
Another important thing to remember is that a person does not have to be a customer or client of yours in order for you to remember their name. If a person is not looking for something you are selling in the present does not mean they will not need something you are selling in the future, and if you remember the potential clients name, you are already that much closer to establishing trust with them and closing a deal. This does not relate strictly to service after the sale but also service for potential future sales.
All in all, developing a relationship with a potential or existing customer is one of the most important things to do in a sales position, and remembering their information for future exchanges is one of the most effective ways for doing this.
.https://www.customerexperienceinsight.com/9-things-you-must-remember-about-customers/
BoweryJE22
You make a really good point here about keeping someone in mind even if they are not buying something from you at the moment. They may come back, or they may get such a great impression of you that he will recommend you to all of his friends and family.