When Westerners enter a bus, a doctor's office, or a waiting room, they sit at least one chair away from the nearest person if possible. Conversation distance with superiors or with those they don't know well is about a meter. However, intimate conversations may be held as close as half a meter apart. Because many Westerners feel uncomfortable if someone stands closer, they will usually move away. If this happens, don't think it's rude. Your listener is just stepping back to their normal conversational distance.