Final answer:
The main idea of the passage is that cultural traditions vary in terms of personal space requirements.
Step-by-step explanation:
The main idea of the passage is that cultural traditions vary in terms of personal space requirements. The passage explains that personal space is influenced by cultural background and can differ from person to person and situation to situation. Examples are given to illustrate how different cultures have different comfort zones when it comes to personal space, such as the distance considered appropriate for social interactions in Mexican and Arab cultures. The passage also mentions that hospitals typically do not define any personal space, further emphasizing the variation in personal space requirements.