I have worked on desktop support and/or helpdesks for several fortune 500 companies. I agree that technical competency is a crucial ingredient to a successful helpdesk. Also, I believe that knowing your client/end-user is a key to success. I have found that some of the more irate-sounding clients will become calmer if you refer to them by their first name when speaking with them. It immediately tells them you care about them as a person, not just another trouble ticket. Sir and ma'am are really no longer required business ethics in today's work-world. Professionals like to be called by their first name, all the way up to the CIO's, CFO's, and even CEO's.