They were not rude to me, exactly.

But they were not warm either.

They had a curious quality I noticed without being able to name, a kind of watchfulness under the surface, a way of paying attention to the room that did not quite match two people out for a romantic dinner.

I filed it away as nothing.

Rich people are often strange, and a good server learns not to wonder about it too hard, because curiosity about the customers is a distraction from the actual work and, more to the point, because the customers do not want to be wondered about.

Your job is to be smooth and unobtrusive and to let people be exactly as odd as they wish to be without ever letting your face register it.