Personally, You want to satisfy your customer, but if they are chatting just to waste your time, don't give them sometime to chat. Once the question is answered, and they thanked you get them out of the chat as soon as possible by approaching a more standard and respectful way.
Say any of the following
You say: "It is my pleasure to assist you today, Is there anything else i can assist you with?"
Customer: "No, So, how is your day going"
You: "Great thanks for asking, Have a wonderful day, and i hope to assist you once again further, if you have anymore questions"
Customer: "Wanna just chat"?
You: "I am sorry, but I am currently under "Your Company name" contract, which I have to abide by, which states that I can not have anything personal with a customer, due to deal issues in the past" I am sorry. good day sir.
This is a way i would approach a customer.