You should also keep a “Willard” organizer nearby so you can calculate the tip.
IMO, if you can't calculate 15 % in your head, you should be eating at home.
It does other things!!!
For good service, 20%, which is pretty easy to figure in your head.
For bad service, 0%, which is even easier to figure.
Or if you’re really bad at figuring in your head, $1 per person if the meals are around $5 each, or $2 a person if they’re around $10 each. And another $1 per person for every $5 per meal (’per meal’ includes drinks and desert).
Occasionally I will treat someone else to a meal. What brings a wry smile to me is when I put in an overtip, and the person who I treated berates me for the tip. I think to myself: "What the hell do you care ya duck. You just ate for free and it's not like it's YOUR money!"