In Chinese culture, the concept of priority is not always based on a “first come, first served” principle, which is often the default in the West. Instead, 优先 (yōuxiān) is frequently determined by social hierarchy and relationships.
Respect for Elders: A core value in Chinese society is 尊老爱幼 (zūn lǎo ài yòu), “respect the old and love the young.” This is why it's universally accepted that the elderly have 优先 (yōuxiān) rights to seats on public transport or service in a queue, often without a formal sign needing to state it.
Hierarchy and Status: In a traditional business or family setting, the person with higher status (e.g., the boss, the grandfather) may be given unspoken priority in speaking, eating, or making decisions. This isn't seen as “cutting in line” but as a natural acknowledgment of the social order.
Comparison to the West: In America, the idea of someone getting priority because of their age or job title in an informal setting can sometimes be viewed as unfair. The default is often egalitarianism. In China, granting 优先 (yōuxiān) based on social roles is a sign of respect and maintaining social harmony. It's an external reflection of an established internal order.