I have a lot of experience with customer service. I've dealt with frustrating customers, and I don't get angry with them, I only focus on the transaction at hand. Getting into arguments only draws out the transaction, which isn't good for anyone.
I'm all about efficiency and try to do a quick, yet thorough, job with whatever I'm tasked to do. It might take me a minute to learn the process, but once it's learned, I work faster and faster. My brain's a little slow, but my hands are certainly not.