Customer is King...
In today's material world, customer is the king indeed! But some customers take this far enough & take improper advantage of this.
A store owner must be patient enough to swallow the unreasonable demands of a customer. Because he may go out and try demolishing your goodwill to 10 other people.
Its an old saying of business in general that "the customer is always right". The point being that, in the long term interests of your jewellery store it doesn't pay to pick a fight with a customer.
You may win the battle, but end up losing the war.
Its also important to understand that some customers may be more right than others & some deserve better than good.
In this regard just be extra cautious while dealing with a notorious customer, but never get into unreasonabe arguement, subtle ignoring is one solution to this.
But do take good care of your frequent/loyal/good customers. Remember them by name, attend them personally, get into chit-chat, give them some extra discount/gifts, socialize more with them.
After all they are the foundation from where you can grow more further.
Read the following lines by Dale Carnegie-"....the best way to have someone take an interest in you, is by taking a genuine interest in them. Show them what you can do for them & they will reciprocate in kind....".