Very smart. Never eat with someone who doesn’t treat the staff with respect or even complains too much...when they throw a grenade at the table you might get hit with the shrapnel. It’s like these people are so entitled they can’t imagine someone messing with the food they are about to consume, or that staff might not have unimpeachable professional ethics. I would hazard very few ever worked in a restaurant.
Freegards
It's also important to realize that the waitstaff are not responsible for a restaurant being understaffed, overpriced or serving substandard food. So taking it out on them serves no useful purpose but to make the most hard working people in the place even more miserable.