People would be offended if you reject their customs.
John is visiting a foreign country with a culture that his vastly different than his.
John wants to enjoy his vacation.
John attempts to immerse himself in the local culture and learn about their customs.
John shows no interest in learning local customs and goes about his business as he pleases.
John has an enriching vacation where he is able to enjoy himself and learn new things.
The locals are offended by John's behavior, so they give him food poisoning and pick his pockets.