I'm on the phone all day long doing high-level technical support for a leading manufacturer of networking equipment. On an average day I speak to people whose tecnical skills are far above mine and people who are just plain bozos. I treat them all the same, politely and professionally. If you are in a service or retail business and cannot do that, then get out. If you own the business, sell it while it still has some value. If you work somewhere, get out before someone calls you on your poor attitude and you get fired. I have owned an IT contracting company and believe me, if I heard someone being condescending, or worse, insulting to a customer, they would be out the door as soon as possible.