Germany
Germans are pretty tolerant when it comes to tourists, but two things really get on their nerves. The first one is taking selfies with memorials for the victims of the Nazi regime, or at concentration camps. They are especially annoyed with those who do funny poses or victory signs. Another thing that you should never do is wear clothing with the swastika symbol or do a Hitler imitation and raise your right arm. Locals take this seriously and you can even get a fine or prison sentence, as it is illegal.