When I was a Director of Human Resources, I worked for a company that had twelve salesmen. Eleven of them were very glib and slick and polished... those stereotypical big, aggressive sales personalities. If a customer asked them a question they gave him the answer he wanted to hear... even if they had no idea what the real answer was. It was all about getting the order and closing the sale.

And then there was Dave. Dave was definitely an introvert. Quiet. Invisible. Unimpressive. When customers asked Dave a question he didn't know the answer to he said, "I don't know. Let me make a call and ask." (and then he called and asked.) Dave's priority was servicing the customer's needs.

As a result, Dave had a ferociously loyal following. Dave made more money than our next 5 top salesmen combined! When I paid Dave, I had to hand him three checks because the highest single check we could issue was $10,000. ...And this was back in the 1980's!