Requesting for modifications to a menu item when you got a restaurant.
The chef works day in and out, and his one job is to make food fast and consistently; and of course taste great. But then a picky eater comes along and says 'can I get this without tomato?' or 'can I get a different type of bread?'
Restaurants are probably one of the most common establishments in the world, and you choose one that you could not find ANYTHING on the menu you liked? Ridiculous and and an insult to the chef. If you don't like their food, don't go there or suck it up. Like seriously, it is one of the most childish behaviors adults are socially accepted to do, because most people treat workers like their personal slaves when it comes to customer service.
I bet it would be a lot different if the chef was taking an order instead of having the middleman of the waiter, lot more respect would be given. Also, I never see anyone asking for these stupid requests when it comes to home meals/potlucks. Probably because you are too scared to hurt Joann's feelings, but no problem when it comes a nameless/faceless restaurant employee.
Allergies are an obvious valid exception.