A gazillion years ago I ordered a pizza delivery from Domino's and when I opened it up there was a beetle scampering about in there. Shut the box and rang them back to tell them.
"We'll send another pizza out and give you your money back."
"Keep the money, keep the pizza, but do send a person to pick this one up...why would I want a pizza from a shop that serves me beetles? This was the last time I'll order."
And it was. Never ever went to Domino's ever again.
If I'm complaining about food to get my money back then I'm just trying to get a free meal.
So if I complain then it's not about me, it's about you and your food. When I order food I am paying for the food and the experience of it, 99% of the time that experience is positive.