I hadn't heard that Walmart story before, but it fits with my experience. I'm a Brit, and Brits are nowhere near the US's level of fake positivity, but the German retail culture was still a surprise to me. It's not that Germans are rude, just not in the habit of pretending.

One of my favourite anecdotes from living over there was from a friend who'd become a regular customer of a particular takeout place. On one occasion he phoned up to place an order only to be greeted with "Oh, it's you again. Why don't you learn to cook?"