You should always tip people.
Frankie is enjoying a meal at the restaurant and is really impressed by how good the meal is.
Frankie wants to let his server know the food was good.
Frankie makes sure to leave a large sum of money on the table for the server as a means of expressing his enjoyment of the meal.
Frankie mentions to the server that the food was good before leaving and paying his bill for just the cost of the meal.
The server that Frankie tipped feels great about himself and is happy he earned such a sizable tip.
The server is annoyed and angry when he finds out that Frankie did not leave a tip despite enjoying the meal.