Customary norms, or 'norma adat istiadat,' are unwritten rules and traditions that are deeply ingrained within a particular community or culture. Two examples include the tradition of 'gotong royong' (mutual assistance) in many Indonesian villages, where community members help each other with tasks like building a house or harvesting crops, and the practice of arranged marriages in some traditional societies, where families play a significant role in choosing a partner for their children.