It would depend on what the first mouthful tasted like.
If it tasted absolutely delicious I would just carry on as per I had ordered it.
This.
I'd taste the pie and if i felt i was getting value for what i was paying I would eat it.
If i didn't think i was getting value i'd ask for a replacement of the pie i ordered without making a scene.
I think this must be the nut strategy. I have never really done this, but guess if it was really horrible I'd send it back. Maybe in future I'll set the bar higher on the "wrong" dish than I would for the original order.
My wife isn't going to make a scene, but she sends straight back if it is wrong.
I have nirvana's aversion to making life difficult for the serving staff. I'd probably tip less, but it would have to be a combination of things, or something really bad to get a zero tip.
Probably a new topic, but I normally round up from 10%, so if it is 55, I will go £6. Might round down to a fiver for wrong pie etc. Sometines go to a tenner for exceptional service/meal. I do like to round up in places like little chef, because it seems such a bad place to work and so many grumpy customers who don't tip. They seem to appreciate it more there. Never tipped in mcdonalds though. Maybe I might start.