I've sent back food a few times. I've even complained in a restaurant in Paris and got treated to a barrage of sneers from the waiter (but got it changed). However, there are times when you grin and bear it: I had a meal in a pub in North Yorkshire that tasted or rotting vegetables in a snot sauce, I'd normally have sent it back but I'd been for a 20-mile tramp in the Dales, had waited nearly an hour for the food and at that stage I'd have eaten grass omelette with dog turd fricasee