While I understand you feel it relaxes people, I sure hope you're from the south or somewhere where using endearments on strangers is considered appropriate. I assume that if you are not, you would be smart enough to adjust accordingly. My dad was in the hospital recently and got called sweetheart by a nurse and was LIVID! To him, it was a condesending insult and, since he was lying helpless in a hospital bed, he did not handle it well. Put it this way, a feeble old man doesn't want to be called one. Seriously, it was a setback for him and could have had horrible consequences for his health.
Could you please explain how being called a name (expecially a term of endearment) could result in a setback or horrible consequences for his health.
Lord help, this is why I don't work with the public.