You don't have to like any of your customers but that is nice. You do have to care for them in as much that you give them the information they need to make a desicion as to if they want to buy your product or not. Also you should have policies in place to protect you and ensure the customer is happy with your product.
I work in retail. Some customers I like, some are friends, some I head the other way when I see them, but if there's a problem I try to find out what I can do to make them happy while not costing me too much. Some times you have to bend a little.