The following occurred over the phone when a client had a minor issue with the site I built for him.
Client: Hi, the margin between the logo and the content is wrong. Can you simply change it while I’m on the phone?
Me: Sure. Did you want the margin to be bigger or smaller?
Client: Can you increase it about by 50%?
Me: Sure. How’s that?
Client: No, that’s not right. It’s too much. Can you decrease it slightly?
Me: Sure. How’s that for you?
Client: Sorry, it’s still not quite right.
After ten minutes of “a little more” and “a little less,” the client tells me it’s spot on.
After they hang up, I realized that I had made a mistake. I had been viewing my local copy of the site, and they had been viewing the live version. I never once uploaded the changed file.