Fighting over the bill
Two people rush to the cashier, hide the bill, or insist louder than necessary. To outsiders it may look inefficient. To insiders it can be relationship work.
Payment as relationship work
The person who pays may express seniority, gratitude, apology, hospitality, or a wish to continue the relationship.
Newer habits complicate the scene: splitting bills, app payments, and younger people negotiating between old rituals and practical fairness.