Explanation:

A gratuity (normally called a tip) is a sum of money customarily given by a client or customer to certain service sector workers for the service they have performed, in addition to the basic price of the service. It may or may not be customary to tip servers in bars and restaurants, taxi drivers (including ridesharing), hair stylists and so on, but this depends on the country or location. Giving a tip is typically irreversible, differentiating it from the reward mechanism of a placed order, which can be refunded.

Tips and their amount are a matter of social custom and etiquette, and the custom varies between countries and between settings. In some places tipping is not expected and may be discouraged or considered insulting, while in other places tipping is expected from customers. The customary amount of a tip can be a specific range of monetary amounts or a certain percentage of the bill based on the perceived quality of the service given.