The word tips is commonly used as gratuity today, many of us may not know where it came from. Have you ever wondered how many words or phrases are tea related?!
Tipping as a response to proper service developed in the Tea Gardens of England. Small, locked wooden boxes were placed on the tables throughout the Garden. Inscribed on each were the letters "T.I.P.S." which stood for the sentence "To Insure Prompt Service". If a guest wished the waiter to hurry (and so insure the tea arrived hot from the often distant kitchen) he dropped a coin into the box on being seated "to insure prompt service". Hence, the custom of tipping servers was created.
It's bribery when a patron had to tip in advance to insure prompt service, where it's gratuity, showing appreciation after prompt service is received. Good service should be mandatory in any service business within reason, so we expect it to be in today's society.
Merriam Webster: Tip - a gift or a sum of money tendered for a service performed or anticipated.