For some reason, I always thought this phenomenon was imported from Europe. I lived in a European tourist mecca for a few years, and whenever I would thank a Eu

For some reason, I always thought this phenomenon was imported from Europe. I lived in a European tourist mecca for a few years, and whenever I would thank a European for something, they wouldn't say "you're welcome" or even an "mm-hmm". Usually they just smiled and nodded. I can see how it might appear a little brusque though. Americans, particularly here out west, tend to put on an air of stoicism, so our "mm-hmm" probably comes without a smile or even a glance in your direction. But I've interpreted that to mean that I am being helped as a matter of course, not for the sake of propriety or some sense of obligation.