You order the shrimp gumbo in one of your favorite restaurants, and when it arrives you spy one lonely, forlorn shrimp floating in the stew. Do you speak up, or swallow your frustration and dig in?

The steak you ordered medium-rare arrives, and the meat is so red you joke that you can still hear it mooing.

You’re in a fussy new restaurant, and you’ve heard the celebrated chef has an ego. When your entree arrives, it’s way overseasoned. You want to send it back, but you’re scared of making a scene.

Complaining in a restaurant is a delicate business. It’s important to get what you ordered without coming off as the customer from hell. On the other hand, you don’t want to be one of those people.

Like the woman who came into 50 Local in Kennebunk recently on $2 tapas night, ordered five plates and ate everything, down to the very last morsel. When she finished, she left a note in the tip line of the bill.

“She wrote down that she hated the food, and never gave us the opportunity to fix anything – but she cleaned five plates,” recalled Merrilee Paul, co-owner and manager of the restaurant.

How do you walk that line between being a good guest and being assertive about getting what you want? We asked several restaurateurs to describe the right and the wrong ways to complain. Their No. 1 response was this: Please complain, and do it before you leave the restaurant. If you sit on it and stew, you’re more likely to unleash the hounds later in an ill-considered one-star review on social media that may be unfair to the restaurant.

Expressing displeasure about food or service immediately “is so important, and it’s so rarely done,” said Michelle Corry, co-owner and manager of Five Fifty-Five in Portland. “We can and will do things afterward, but it’s just so difficult to satisfy you after the fact. And a lot of the (problems) are such easy fixes.”

Start with the server or manager, especially if you have a straightforward problem with the food – the soup could be hotter, or the chicken is dry. Don’t flag down the busser, who likely hasn’t been fully trained to deal with this kind of issue, or ask for the chef, who has a whole kitchen to run so doesn’t have time to deal with individual complaints. If you must get a message to the chef, Corry suggests, relay it through a manager, or ask for the chef’s e-mail address.

“I’ve had times when customers will walk plates back into the kitchen,” said Donald Linscott, manager at Sea Glass, the restaurant at the Inn by the Sea in Cape Elizabeth. That’s a big no-no.

While you’re complaining, Linscott adds, throw in a compliment. That “shows you are a reasonable person,” he said.

If the issue is service – an entree took too long to arrive, your server was AWOL most of the night – ask for a manager. The manager is the one who can correct the problem, especially if there are multiple complaints, either by talking to the server or offering more staff training.

Deen Haleem, owner of Tiqa restaurant in Portland, says the vast majority of complaints he hears about service come through social media. “You have no idea who they’re talking about,” he said, “so you have no idea what to do with that information.”

Restaurant managers are often happy to comp food if the offense warrants it. They’ll also offer gift certificates for return visits. But don’t come in expecting a lot of freebies, especially if you’ve eaten all but two bites of an entree and only then decide that you don’t like it.

Most managers will try to fix a problem first. Not enough broccoli on the side? Linscott will send out another serving. Meat too rare, or overdone? Re-fire it, or offer another entree gratis.

This summer, when The Good Table restaurant in Cape Elizabeth was short-staffed and had a new chef, the staff sometimes had trouble getting food out promptly, owner Lisa Kostopoulos said. She comped a lot of desserts, bought wine for people, and took entrees off the bill. “I gave my managers carte blanche,” she said. ” ‘Do what you need to do to make people happy.’ ”

She also likes to give gift certificates so people will return and give the place another chance. Most people just want to know that they’ve been heard, Kostopoulos said.

But, she says, there are limits.

She cites the couple from New York who were eager to try haddock for the first time. When the couple finished their fish, the man told Kostopoulos they didn’t like it and wanted it taken off their bill. Kostopoulos told him that if the fish were bad, she would understand. If it were cold or not cooked properly, she’d understand. But if he chose to try a dish and didn’t like it, that’s not her fault.

“He was incensed with me and he kept trying to make deals with me,” Kostopoulos said. “He said ‘Well, if we order two lobsters and a bottle of wine will you take it off the bill?’ I said ‘No sir, it’s the principle of it. You chose to try something new and you didn’t like it, so I don’t need to pay for that choice of yours.’ ”

The couple ended up walking out of the restaurant without paying any of their bill, and later wrote a long, negative review on Trip Advisor.

Paul also has her limits.

If the issue is “clearly our mistake,” such as meat that’s been cooked to the wrong temperature, she’ll send out another plate at no charge. If a customer barely touches an entree and says he didn’t like it, it will be taken off the check and the person will be offered something else. What irritates Paul is the diner who says everything is fine when the server checks in halfway through the meal, then flip flops when just two bites are left and the table is being cleared.

“That’s when I cannot take this off your check,” she said. “I just can’t. I can come talk to you about it, and maybe I’ll send you a little cookie or beignet or something because I want everybody to leave happy and want to come back.”

Paul points out that this would not be acceptable behavior at any other small business. Who goes to get a 90-minute facial, she asks, and with five minutes left declares, “You know what? I’m not really enjoying this.”

But other managers believe that old adage that “the customer is always right” applies to the restaurant industry.

Corry said she thinks restaurant people sometimes forget what an important occasion dining out can be. That couple sitting at one of your best tables may not have been out together in six months. They saved up, got dressed up, and paid handsomely for a baby sitter.

Staff illustration by Michael Fisher

“If something goes wrong, it may not seem like a big deal to you, but it does to them, and we have to respect that,” she said.

Daron Goldstein, who opened Provender Kitchen + Bar in Ellsworth in November, considers dealing with complaints part of the cost of doing business.

“People pay good money for their food,” he said. “We should live up to their expectations.”

If a diner orders a steak medium rare but claims it’s raw after taking a bite, Goldstein will throw it back on the grill for a few minutes even though he knows the meat was cooked perfectly. Once a couple ordered a $120 bottle of wine, and after drinking a good portion of it, they insisted that something was wrong.

“We thought it was fine, but they didn’t like it,” Goldstein said. “Did we charge them? We ended up just comping it.”

Some in the restaurant industry say that diners are becoming ever more vocal, and the style of their complaints has changed, as they have become more knowledgeable about food.

“We have such extraordinary food and such extraordinary experiences (in Maine) that the bar has been raised,” Kostopoulos observes. “Sometimes I think that good, honest, average food kind of gets pooh-poohed, like there’s not enough ingredients or there’s no truffle on there.”

Linscott says complaints today can be more nuanced. If a customer orders a rabbit rillette, for example, she is expecting a French dish, but maybe the chef has made it with Indian spices.

“I always have a conversation with servers in the dining room where we’ll talk about expectations, what people think they’re getting,” Linscott said. Giving diners a heads-up that their rustic olive tapenade might have a little heat from a sprinkling of chili flakes will help avert any surprise or disappointment they may feel when they take their first bite.

Haleem has also run into this issue. Every spring and summer, the chef at Tiqa puts a scallop dish on the menu that includes corn served, intentionally, at room temperature. Some diners expect the corn to be warm. Now the server warns them in advance.

Lisa Kaldrovich, manager at MK Kitchen in Gorham, says she tells her staff to try to find problems before people complain. She goes out to “touch the tables” as often as she can, and sometimes pushes her chef/husband, Mitchell Kaldrovich, out of the kitchen to visit with diners.

“I always say if you see somebody’s attitude changing throughout the meal, then it’s our job to figure out what (the problem) is,” Kaldrovich said. “If someone has a full plate and they’re not really eating it, then it’s our jobs as servers and hostess to check in and directly ask them if they’re happy, or is there something we can get?”

An attentive waitress helped Union residents Cindy Rogers and her husband, Glen, take care of an issue recently when they had breakfast at the Home Kitchen Cafe in Rockland. Glen’s home fries were undercooked inside. “The waitress came over to see how everything was,” Cindy Rogers said, “and she could kind of see that he wanted to say something and didn’t.”

Cindy Rogers said she’s usually shy about complaining. Ordinarily it would have to be “something pretty bad” – like a hair in her food – for her to speak up. But this time, she told the waitress what was wrong, and finished with, “otherwise, everything’s really great.”

Glen refused another serving of potatoes, but the waitress didn’t let the matter go. She informed the cook, and then quietly handed Glen a free cinnamon bun.

Corry says that 99 percent of the time, customers aren’t expecting anything in return when they complain, particularly about something minor. When a couple recently emailed Corry a note about a disappointing experience at Five Fifty-Five, she emailed back immediately to apologize and offer both a refund and a dinner for two, “like a redo.” She says she could tell by the note that they were offering feedback, not looking for freebies. The guests came back in a couple of weeks ago, “totally thrilled and totally thankful.”

Satisfied guests are guests who return again and again. So complain away – within reason.

“We’re here to make you happy,” Corry says, “but help us help you.”