can already tell you'd be a right pain in the ass to go to a restaurant with, do us all a favor and don't offer your terrible advice to anyone anymore.

I can and I will

If that were my mother or any other family member doing that in public I would be livid and embarrassed. You don’t get any right to treat workers like that, especially when it’s not a waiters fault or when there is a slow order because of a previous order. You don’t know why the orders were delayed but you don’t freak the f**k out over it. Her reaction is not justified. It is childish and shameful.

Have you ever worked a job before? Its not easy. Its completely possible that they merely were overcrowded. Or too busy. It's not the end of the world if your order doesn't come in soon enough. Their mother had no right to act in the manner she acted in. I can excuse it, if she isn't in her right mind. But when people work hard for you, you should be respectful of that. I can see someone politely informing their server they didn't like the wait. But throwing a fit is childish and shameful. Manners are a thing.