"Based upon the way you're dressed and what you do for a living, and the way I'm dressed and what I do for a living, you're under the assumption that you are smarter than me. There is a very large chance that the reverse is actually true"

Yup - said those words out loud to a (potential - but not really) customer when I worked retail a few years ago. Not the first warning to myself that I needed to do something different, but I was out less than 4 weeks later.