I used to work retail as a kid and at that time I learned two tricks. The first was for normal people (like you seem to be) and it was simply to put myself in

I used to work retail as a kid and at that time I learned two tricks. The first was for normal people (like you seem to be) and it was simply to put myself in the customer's shoes. Generally a person isn't going to pester you over a $9 cable so those who do pester are making long term purchases. That means they are speaking to you about something that will affect their life for years to come. If you as the salesman remind yourself of how important this purchase is to the customer I find it keeps frustration down. The second trick was for the really obnoxious people and it basically boils down to invoking pity. I found it is very hard to stay angry at someone you truely pity. So in the case of really obnoxious people who got me angry I'd remind myself that this person probably treats everyone in their life this way and basically lives a life in which everyone regards them in the same angry light I do. A life like that can't be easy to live and the truth is it's probably a vicious cycle (they treat people badly so people hate them more which leads them to conclude people are all mean and treat them even worse and so on.) So the truely obnoxious live in a hell of their own making and that's really, really sad when you think about it.