CNN’s Eatocracy blog recently told the unfortunate tale of a “sender-backer.”

“A what?” you ask.

A sender-backer, as in a cretinous man who makes a habit of cadging free meals from restaurants by sending back mostly eaten entrees. The CNN reporter who wrote the post had the (mis)fortune of sitting next to this man in a New York restaurant. After the guy sent back his steak, he explained the technique to his date. After sending back a small remaining portion of his dish, most waiters will ask if he’d prefer a replacement entree or having the item removed from the bill. He always chooses the latter.

People like this are doubly odious. One, because most restaurants operate on paper-thin profit margins and they can’t afford to entertain jerks like this. Two, because he makes a bad name for the rest of us who send food back for good reason.

Most people I know never send food back. Even my wife demurs, preferring not to make a fuss because she’d never want to be mistaken for anyone remotely like our friend the sender-backer. She’d rather push around an inedible entree than be seen as a pushy broad.

Me, I’m a firm believer in sending food back — but in the right way.

When and how to send food back depends very much on the situation. Let’s look at a few scenarios:

1. There’s a foreign object in your food. It happens, even in the best restaurants. I have found all the usual items, as well as a sharp piece of metal wire from a twist tie in a salad, and a live worm crawling about the greenery that accompanied a bowl of pho.

I have also personally worked in kitchens where dishes come back — and not only with errant hairs. I’ve had to respond to buckshot in venison and, believe it or not, a men’s wristwatch in a salad. The latter we traced to the produce delivery guy; the cooking student in charge of the salad station got a stern talking-to about being more careful when cleaning lettuce.

If you find something that doesn’t belong in your food, call the waiter and — without question— ask to have your dish replaced. If you’ve already eaten most of it or feel too disgusted to eat anything more, alert the waiter, politely refuse replacement and let them decide how to handle the complaint.

2. Your food is over- or undercooked. Some steakhouses ask you to saw through the center of your steak to make sure it is cooked to your liking. If not, it’s still a good idea to make a cut somewhere deep inside the steak to check.

If the steak is undercooked by a degree of doneness or more, you can ask to have the same piece of meat cooked further.

If it is overcooked, you can ask for a fresh steak.

With other kinds of protein, it’s a good idea to first find out how the chef prepares it. Some like to serve medium-rare salmon or pink pork chops. If that’s not for you, make sure you discuss your preferences with your waiter when you order.

So what about other foods that can be over- or undercooked — burnt pizza crust, say, or cold-centered eggrolls? Return them: You shouldn’t have to pay for, or eat, food that isn’t prepared correctly.

3. Your food is, for reasons particular to you, inedible. If you’ve got an allergy or a condition, such as celiac disease, that prevents you from eating certain foods, then it goes without saying that you should alert the waiter before ordering.

But what if your entree arrives and, without warning, is spicy enough to merit a “three chiles” rating on a Thai menu? Or what if you order a light-sounding pasta that comes swimming in an unannounced cream sauce?

I think, in these situations, you have every reason to send your dish back and expect a replacement. If you’ve made a good-faith effort to find out about a dish and discover it’s extreme in a way you can’t stomach, the restaurant needs to do a better job of describing it.

4. Your food is clumsily or poorly prepared. So the bottom half of the hamburger bun arrives so saturated with juice that it falls apart. The mixed greens, right from the bag, have those squiggly wilted bits that look like algae. The shrimp haven’t been deveined. Here’s where things start to get tricky.

You should definitely draw your server’s attention to the problem if it bothers you enough that you don’t enjoy the food, but let him or her offer to replace it. Or not: This is the litmus test.

If you’re at a well-run restaurant that maintains certain standards, then they should admit they’ve let you, and themselves, down. Mistakes happen, and everyone will be happier when standards are upheld.

If you’re at a restaurant, however, where the bar is set low and no replacement is offered, then you should suck it up and strike the restaurant from your list.

5. You just don’t like the food. The sauce is a little salty. The chicken lacks flavor. There’s a spice in there you don’t appreciate. Should you return any dishes for these reasons?

No, but if the waiter asks how you like the food, be honest.

I recently ate at the restaurant John Dory Oyster Bar in New York. I started with two small plates and ended with a soup called “lobster panade” for my entree.

The waiter had warned me the soup was thin and didn’t have any lobster meat, and the dish proved him a man of his word.

It was a russet broth made from the deeply roasted shells, with a caramelized — almost burnt — flavor lurking inside. I didn’t find it appealing.

When the waiter came to ask how it was, I responded, “Fine.” I wasn’t going to lie and praise it, but I wasn’t going to make a fuss and complain. Fine was an honest response.

“Just fine?” he asked, astutely picking up the clues. “We can always get you something else.”

I insisted I was copacetic. Then he said something really smart. “Just flag me down if you change your mind.”

After five minutes of pushing the soup around, I called the waiter over and ordered chorizo-stuffed squid. I loved this dish. “Are you going to finish the soup?” he asked. When I said “no,” he quietly cleared it away.

The bill came, and the waiter told me he didn’t charge me for the soup. “You didn’t like it, so you shouldn’t have to pay for it,” he insisted.

This, people, is the definition of good service.

That said, I was ready to pay for the soup.

All you can expect a restaurant to do is replace a dish you return. Do not expect them to take it off the bill, or offer free dessert or drinks. If that happens, then appreciate the hospitality and reward the restaurant with your continued business.

But once you start expecting freebies, then you’re no different from Mr. Sender-Backer.

Join the conversation at blogs.ajc.com/food-and-more. You also can e-mail John Kessler at jkessler@ajc.com.