Some westerners may be offended if you touth them or their personal things ----even by accident. If this happens, say sorry politely.
Some slderly westerners may be offended if you try to help them without their agreement。
People think numbers can be lucky or unlucky .Some westerners avoid the number 13 because they believe it is unlucky.
Muslims do not eat pork,and words like pigs are considered improper.
People from Brazil,Italy and Pakistan do not give handkerchiefs as gifts.They believe a handkerchief is connected with unhappy feelings.
Wine is not a proper gift in many parts of western and middle Asia,where most Muslims live.