I agree with this 100% up until the last sentence, where he clearly indicates that he just doesn't get what's actually happening in these cases. Where I see thi

I agree with this 100% up until the last sentence, where he clearly indicates that he just doesn't get what's actually happening in these cases. Where I see this happening, is when people say "Thank You" over-enthusiastically, or in response to things that were done as a matter of course and deserve no thanks. The person being thanked is taken off-guard and slightly embarrassed to have been thanked for something which he would have done anyway. It feels like saying "You're Welcome," would be to acknowledge the thanks-worthiness of the act in question, which would be a form of dishonesty, so they can't say that. On the other hand, it would be unambiguously rude to say nothing, so they mumble something non-committal in a vague attempt to to say, more or less, "Really, it's nothing." Why don't they just say that? Probably because they are taken off guard and slightly embarrassed Really? Because I've scored the old "mmm-hmmm" from perfectly normal "thankyous" performed for perfectly normal services. "I'd like a cup of coffee" "Here you go" "Thanks" "Mmmm-hmmmmmm" In Australia we'd just go "Sure" or "No problem" or something. "It is curiously moving to see them sitting looking a little embarrassed as a pilot or flight attendant calls on their fellow passengers to give their service and sacrifice a standing ovation." I've never seen anything like this, I can only imagine that being embarrassing all round if it ever happened. Though I certainly have seen soldiers looking embarrassed upon being thanked by random strangers in airports.