Another one I have; after they ask, "How was your meal?" is...
After a furtive glance around; lean in a bit closer and say...
"Well; normally I wouldn't complain; but the meat: it tasted like flesh from a dead animal."
To my delight; she'll get a shocked look and say, "Would you like to speak to the manager?"
lol. spot on.
but i do empathize some with that poor waitress, on her feet all day and harried by weekend customers having a leisurely sit-down dinner while worrying her about that “fungus” on the steak :).