We are people starving for attention in a world of automated tellers, touchscreen ordering and voice response systems. Personal attention is a two way street. That person behind the counter who robotically rings up your purchase needs attention as much as you do. We are human and our spirit is what separates us from the animal kingdom.

In my industry I work with people who suffer test anxiety since their credentialing and livelihood depends on a high stakes test. Experience has taught me that acknowledging it in some way from the beginning returns a heartfelt "thank you" afterwards. One way I do this is just prior to entering the test room I will tell someone to "take a deep breath, breathe in the good air, exhale the bad air and think success." There is nothing original in that statement but it gets a positive response in test takers ranging from burly firefighters to aggressive stock brokers to aloof doctors.
At the interchange of human interaction people seem to be dispassionate but underneath they are not. Inside may be a raging bull or a soft-hearted bear that fears what others might think or only wants to be recognized as a person. Take a moment to recognize someone's fear or anxiety by doing or saying something that acknowledges those emotions indirectly by being personable. My bet is that you will discover the most detached person will light up and respond.