If you do have an occasional run-in with Mr. or Ms. Nasty, here are some common misconceptions you might want to think about. Nasty customers may lie. Just because they told you they could get the same piece a lot cheaper from someone else, doesn't mean that they can. They just want to see if they can play with your head, or put you up on the auction block over price. If you know what's right, stick to your guns.
Nasty customers can be wrong.
With nasty, arrogant customers, you can afford to be arrogant as well. You can also be ignorant to their demands. You can be ignorant, or you can be arrogant, but you can't be both at the same time. If you're both, you might turn into a nasty yourself. Just because nasty customers are satisfied doesn't mean they're coming back.