A tip (also called a gratuity), that is a payment made to certain service sector workers in addition to the advertised price of the transaction (Wikipedia), is a common practice in most countries, though tipping varies among cultures. While by definition a tip is never legally required, and its amount is at the discretion of the person being served, in some circumstances failing to give an adequate tip, may be considered very miserly or unethical. In other cultures, giving a tip is not expected and offering one would be considered condescending or demeaning. What is the situation in your country? PS. If the topic has already been discussed ignore it!