I own a business and this is how I deal with it:

I explain that if a rude customer is a cash cow...just suck up and take the abuse...you'll see it in your year end bonus. If not, tell them to go and do something very anatomically difficult.

Every employee laughs about this...and understands it...and looks forward to their pay envelope. They also know that I do the same thing.

Rude = Higher Prices

Nice = Normal prices