My son is a chef. He’s heard all the dodges to get free meals and sometimes they actually do screw up and will comp it.
The one he likes to tell is an older couple came in and shortly after they got their order they called the waitress over and complained about something on the wife’s plate. So the waitress takes it back and they do another plate.
Meanwhile, the husband is sitting there not eating, so when they bring out the wife’s new plate, he complains that his food is now cold. You can see where this is going.
The waitress takes the husband’s plate back to my son and tells him what happened. My son goes out to the couple and politely says, “Unfortunately, it looks like we’re not going to be able to satisfy you today. So, we’re happy to cover your drinks and we hope you can find a better meal elsewhere.” and then showed them the door.
