If you are an American in America, there is no discussion. Tipping is a way of life. If somebody performs a service for you, from opening a door to waiting on your table at a restaurant, they expect, and you will automatically oblige with, a tip.
The going rate in the United States is, I believe, at least 20 per cent of the bill in a restaurant, and at the very least, a few one-dollar notes for a random nicety.
But tipping is not a universal thing. In some places it is not only not expected, it is actively discouraged. Why? Because it gives employers an excuse to pay their staff wages below the poverty line.
Many of us want to give tips as a reward for good service. But then there’s a problem: we don’t know where the tips go.
We may think we are rewarding an individual for exceptional service, but the establishment may have a policy of putting tips into a pool, meaning the money is shared among all staff, including those with whom the customer has had no contact. And including the staff member who was rude to you, or the one who wasn’t even there when you were.
Some places have a formula for sharing the tip, with managers getting more than floor staff. So the person who is already on a higher wage, with whom you have had no contact at all, gets more of your tip than the person who gave you great service.
In some places, tips are pooled and used to pay off extraneous expenses — for example, the bills of customers who flee without paying — before anybody sees any money.
My advice is: ask what the tip policy is. If the individual, or individuals, you want to reward are not going to get the full benefit of the money you give them, then make a noise to management. If in doubt, don’t tip.