Ahhh, you jogged my memory of another one. Probably the trashiest, since it took place in a wealthy suburb where people fancy themselves better than other people.
From a Yelp review I left: “A family in the table to my left and in front let their child (6 or 7, mind you) take off his shoes and run around. He then ground his heels into the carpet - with a piece of chicken in between. He swiped a cloth napkin from an empty table and rubbed it all over his feet. I audibly gasped, but his obese mother couldn’t hear me or ignored me. Then she threatened to take each of their Kindles away if they didn’t shut up. The boy was eating with salad tongs instead of a fork all night long.” The staff did nothing at all; only later did I find out that the management had changed recently.