Agreed.
Also, I disagree with the statement that “tips are not optional.” They should be optional, unless the restaurant makes it clear before you order that there is a mandatory charge. I don’t like that, but they are entitled to do it.
If you’re working as a waiter or busboy, do your job, and somebody doesn’t tip, it’s enough to annoy anyone. But you just have to lump it. And occasionally you’ll come across someone who tips very generously, which makes up for the cheapskates.
As I said, I don’t eat out very often, because I can’t afford it. But when I do, I remember all my kids and their stories, and I usually give a 20% tip, especially if the bill is modest.
I believe the menus state the fixed gratuity for parties of a certain size, or larger. I think it was printed on the receipt, as well. Even when I'm in a group, I always leave a tip, but when it's just my husband and me, he lets me decide the tip. I've never worked as a waitress, but I've had friends who have, and they do have to work hard for their money.