Destiny’s Child had it right… “say my name say my name…” In their song, it was meant to test whether the singer’s partner wasn’t confused about who he or she was with. The idea was that if the person was using filler pronouns rather than the singer’s proper name, it was a sign that the partner might be philandering. Names mean a lot. Remembering a name can help establish rapport quickly.
On that note, not bothering to remember or refer to someone but to fill it in with a title creates an unnecessary distance between the speaker and the person he or she is speaking with.
The words? “Sir” and “ma’am” (and other similar ones like “miss”, “officer”, etc.).
These create barriers. If you want to refer to them by a name but don’t know it, ask. Or, address them by their full title and name. Ask. Or don’t pretend that you have some relationship.