What to do and not to do while travelling to other countries

Don't cut in line: "Queue jump — this is the only crime that the population would consider bringing back capital punishment for." Don't ask how much money someone makes: "Instead play a curious guessing game by asking someone what they do, where they live, where they went on holiday, and figure it out by correlating this with their accent."  Don't invite someone to your home: "Unless you know them very very well."