I only had to do that one time. With fettucine alfredo I was not about to eat it cold. I politely told our waitress that my meal was cold and she was very nice about it and took it back and brought it back hot. I know these guys work hard, and I know that there's a lot of jerks out there that will complain at anything.

As someone who worked as a waitress, I have never actually seen someone spit on a customer’s food. Although some customers would have deserved it, we would get fired if we did. In most cases if the food is cold then the wait staff will be understanding and ask the cooks to remake it. What’s annoying is when you are waiting on someone who continuously complains about the food being cold after you just got the food right off the stove, which happened to me quite a bit.

I went to a fancy joint one time. Paid 15 bucks for a bowl of soup, gazpacho I think it's called, and they had the nerve to send it out cold to me. Never goin back there, and they heard an earfull on yelp, lemme tell you.

It would depend on how regular a customer I am.
What sort of wait staff doesn't check the food they're bringing out is in the ballpark of appropriate temperature.
I worked in a high end seafood restaurant early 20s and while it wasn't an everyday thing saw stuff like dishes being split with bare hands for certain high maintenance patrons who appeared to delight in being waited on....a great deal, to their peril.

Wait staff only do the spitting thing if you're an actual asshat. Be kind and non-judgmental in your request and there will be no spitting.

Yes I would.

Is this a hypothetical or did it happen to you? If the latter, how did you handle it? Seems to me your trust in people is broken. Unless you’re mean or unreasonable, wait staff treat customers like decent human beings. I have sent dishes back in more than one occasion for different reasons. I nicely explain why and ask the waiter to bring another.

Send it back!
I have sent food back a bit - not frequently - for a variety of reasons; not cooked as requested (mostly steak), not expected quality (I once sent a salade nicoise back because the tuna was out of a can), next course arriving before the previous course was finished (in which case I always insist that a new meal be prepared, not the existing on kept warm).
I have on very few occasions sent wine back, but that doesn't happen any more with Stelvin closures.

I don't think sending food back annoys or upsets most wait staff when there is a legitimate reason for doing so. It's HOW one sends it back that matters. Rather than getting all pissy with the server, speak to them as you would an ally. They want a good tip, and most will make an effort to see that you enjoy your meal. If you treat them badly or give them reason to believe that you may stiff them on the gratuity, you're fair game - and justifiably so.

Your suspicion of restaurant staff is unwarranted.

For years, I worked as a waitress to pay for my bachelor degree. Nobody ever spit on a customer's food.

When kitchen staff made a mistake, they promptly corrected it. Often the customer was not charged for their meal.

I'd be kind about it, it allows two things to happen...a mistake to be corrected, and their tip and service to remain at a good level if they took care of it.

walk off unless it was key lime pie.