Respects for elderly and superiors (by age, position, monks, or certain professions) is Thai mores. As with other Asian cultures, respect towards ancestors is an essential part of Thai spiritual practice. Thais have strong sense of social hierarchy, reflecting in many classes of honorifics. Elders have by tradition ruled in family decisions or ceremonies. ''Wai'' is a traditional Thai greeting, and is generally offered first by person who is younger or lower in social status and position. Older siblings have duties to younger ones. Thais have a strong sense of hospitality and generosity.