A few years ago I went to a (very expensive) restaurant with a friend of mine (call her J) who is extremely allergic to onions and related plants like garlic and chives. Allergic in the sense of anaphalaxis, carries an Epipen, has-ended-up-in-intensive-care-before-no
Whe the waitress first came over, my friend explained about her allergy, and asked if she could speak to the chef who would make her food, so she could check there weren't any hidden onions (because sometimes dressings and stuff have tiny amounts of garlic or something that isn't obvious) and so she could let him know to be careful about cross-contamination from pans, chopping boards etc that had been used with onions.
Chef's fine with this, they agree a dish that is definitely uncontaminated with onion, she orders it. Unfortunately, there was a mix up with the trainee chef who garnishes the finished dishes, and he'd prettified it with a pattern of criss-crossed chives. Not good, but hey, mistakes can happen.
J points this out to the waitress and asks her to get the chef to remake the dish. Waitress looks annoyed, but takes the dish and disappears. She comes back about 4 minutes later with a chive-free plate.
Now 4 minutes has no way been long enough to remake the food. So the following conversation ensues...
J: Has this been remade from scratch?
Waitress: Yes, like you asked because you didn't like the chives.
J: I'm sorry, but I think this is the same food, with the chives taken off. Could you ask the chef who remade it if I could speak to him, please? (because she's pretty sure the girl is lying)
Waitress: Oh, all right it's the same one. The chef's busy, so I didn't bother him. There's nothing wrong with this food, I've taken the chives off now...
Fortunately the manager, when summoned, was not of the same opinion and arranged for a replacement. But nevertheless the girl continued to act as if J was being a complete entitlement bitch and making a fuss for the hell of it for the rest of the meal. She then had the gall to mutter something when J told her that she would not be leaving a tip.