Without implying that the advice before the edit was any less useful - because that was definitely very good advice - the one you addded in the edit is a gem of a practical advice, especially for me.
I think I was susceptable to getting distracted by "interesting" stuff and it might have helped me get tagged (albeit, unwillingly) as an asshole in the past.
I am probably generalizing when I say this, but to some extent, you will find in that business that a good chunk of your clients will be using your services for the sense of luxury it gives them. It's often decided on a whim, as an indulgence. So chatting up clients as "class peers" often ruins this fantasy for them. For many of them it's their chance to get spoiled and catered to, so "yes sir, yes ma'am" is all you should say to them.
Another thing is that people, specially the well off and people in sensitive positions are weary of having someone with a clue in their house. It's not unusual to overhear sensitive conversations. So, try to be dumb and folksy.
Cheers!
I hadn't thought of it that way till now, but now when I think back, it does make a chunk of sense. I might even have unwilling intimidated some, by talking about stuff they didn't know (they, as in customers)
The point about "sensitive positions are weary..." thats another good one.
Who knows, may be HN (and the contributors on it) would be the perfect educators for me to get out my social awkwardness!!