On convoy from Holland I tried to buy some coffee from a German girl running the reforger refreshment stop stand, I asked her if she accepted Dutch money and she snapped at me, saying “they’re German aren’t they” in a really nasty voice, that was my first introduction to Germany.
Back in the final days of separate currency in all of the EU when they were double pricing in Euros but still using the local currencies, I asked if they would take my DMs in Holland. They were happy to do so, but said they would have to give change in the local currency, which was fine with me. I still have the colorful Dutch currency.
Obviously, she could tell what you were like.