Only your loyal customers will come back. The trick is to switch customer satisfaction to customer loyalty. You must decide. You are in control. Handling nasty customers effectively means being in the driver's seat.
Nasty customers can be opportunists.
Gimmee, gimmee, gimmee. Give them an inch and they take two miles. Don't expect to get back as much as you lay out for a nasty customer. They always want to be one up. They like to think that they are the world's best negotiators.