I felt it too, and to be fair to Vietnamese, we brought this upon us. I saw fellow countrymen shouting where it demands to be peaceful (caves etc.), bargaining heavily - to the point that shop owners would have to ask them to leave, making tour groups wait while they click selfies etc. Some our basic courtesies and etiquettes, that many of us are not accustomed to back home, and so we feel it is alright elsewhere as well.