Hard to believe, but people in the restaurant business have their beefs about customers.

One common refrain heard from the restaurant pros who answered my recent query about what bugs them: "It seems like everyone is an expert on how to run a restaurant."

Read more: What bugs us about dining out

Especially those who post on social-media sites such as Yelp, Facebook, and TripAdvisor, where the commentary varies from fair criticism to outright lies.

Why is it — as one commenter asserted — that some customers go “immediately to Facebook or Yelp when they feel slighted, regardless of whether their facts are correct? Quick to fire off bad reviews that stick forever without any oversight.”

And never say a word at the restaurant, especially an issue that could have easily been rectified.”

"Or even told the server everything was good but still proceeded to write a negative review."

"As my transmission guy said to me, 'If you have a problem, talk to me, not about me.' "

"Even though we give 100 percent, mistakes happen, and we can't fix what we don't know about."

"Most chose 'cruel intent' and 'judgment' over actual items that misstepped during the meal. It seems intentional. I try to not make it hurt, and move on but it does affect me and most of my peers, I'd think. Nice Yelps are helpful too, but it takes 10 nice ones to equal one tough one."

"And 10 Yelpers are hard to find," came a reply.

"We just had an issue where our glycol [beer-cooling] system broke down right before happy hour. One customer came and was bent out of shape that she couldn't get the beer she wanted that we had advertised was on draft special (but couldn't serve at that moment due to the glycol system) and that the bar was packed. She was offered a table and declined. Then went to Facebook and gave us a one-star review and claimed the host said we were closed to the public (we weren't) and that we falsely advertised a special that no one could have (the only reason was the suddenly faulty draft system). The best part was she owned a bakery, so I hope her equipment never breaks down."

Also:

"Had a Yelper complain that our grass-fed burger was too 'bovine.' "

Moo-ving on now…

The reservation game

"No-shows and people who are late for a reservation but don't call." (Note to offenders: OpenTable and Reserve allow restaurants to note these transgressions. Some restaurants create black lists of deadbeats.)

"When a party of five-plus has shrunk to two people, and you're informed when the two show up (after you've had to turn people away)."

"A guest who demands something free because we are late in seating them. Do they demand a free flight when their plane takes off late?"

"The regular guest who insists on having 'their table' every time they come in, and will throw a tantrum if they do not get their specific table. I've had some of my most consistent regular guests actually screaming and cursing and walking out for not having their preferred table ready. When you are a regular guest and we accommodate 'your' table 98 percent of the time, you have to have some understanding the 2 percent of the time we don't."

"Making an OpenTable reservation for two and showing up as a couple with a 1-year-old and a huge stroller."

Attitude

"People who treat servers like servants."

"Finger. Snaps."

"I've seen grown women and men speak so condescendingly to our lovely staff, it hurts me. It happened to me multiple times over my career, and I had no problem dealing with it, but it's a whole other thing watching people treat our employees that way. It makes me want to throw them out and ask them never to return, which is a dangerous practice. Maybe someday."

How to tip?

Restaurant staffers say that a 20 percent tip — not 10, 15, or 18 percent — should be standard. But one commenter called out customers who "don't tip on comped or discounted items, and who think you don't tip on the tax." Yet many restaurants calculate a suggested tip and present it on the printed bill — and many calculate on the pretax total.

At the table

People who say: "I know the owner." ("I love telling guests, 'So do I.' ")

"People at large tables who loudly dominate the room."

"Customers who come in and demand to change the environment to suit them. Air, heat, music, etc. Eat at home if you're so delicate."

"When adults don't know how they like their meat cooked and they look at their spouses or significant other to respond." (Another commenter suggested that it might be a cultural thing.)

"People who sit there and let their food get cold while they compose the perfect shot for their Instagram post and then complain about it being cold."

"People who come to a restaurant for the cuisine and then proceed to make special requests and deconstruct everything unique out of the dish."

"Two people who insist on sitting in a table for four. This gets amplified just before an expected rush, when they also give you the 'there's plenty of room' battle. This is always followed by a completely seated dining room and these two taking twice the average turn time and only drinking water at a four-top."

"Not leaving when it's closing time and you clearly see you're the last table."

"Lingering a long time after you've paid your bill when it's busy and other people are waiting to be seated."

"People who apparently live in a zero-defect environment, so they feel obliged to be critical down to the weight and tapered handle of the cutlery and then take out their neuroses on the servers."

The “I’ll have a cup of tea” echo at a large table when you’re slammed. #drinkteaathome #ladieswholunch

From the kitchen

"Adding an egg to a burger then asking the kitchen to cut it in half. … Nothing says you and your job are the scum of the earth like asking to cut a burger in half. 1. You have a knife at the table and we will be more than happy to bring you a steak knife.
2. Our job is to make sure everything looks great going out of the kitchen. A burger flopping on its side does not."

"I had a woman ask me to cut a hot Bavarian pretzel into six pieces, an empanada in half, and a bao bun in half. Should I chew it up and spit it into your mouth like a baby bird, too?"

"Those who don't read the menu and then want to send something back after it's received at table because they didn't know it had a specific item that was clearly listed on menu … and even worse when they don't feel bad about it."

"Diners who order duck breast or rack of lamb very well done. When warned that it would be dry, they insist — and then send the dish back because it was too dry."

People "not being aware of their surroundings, especially in [upscale] restaurants. … I was at an Italian restaurant and a guy got huffy and talked condescendingly to the bartender on why they do not carry Michelob Ultra like Chickie's & Pete's does."

"How half of the population suddenly became gluten-intolerant overnight." ("If you don't like something, you are NOT allergic.")

"When people pick and choose components from other dishes to make their own dish and then send it back saying they didn't like it."

"Sending things back to the kitchen not because they are not properly prepared but because the patron is an idiot. The chocolate cake is too chocolatey. The biscotti are too dry. The coffee cake doesn't taste like coffee."

"A customer asked for french fries without looking at the menu. I said we don't have french fries but we do have mashed potatoes. He said, 'Even McDonald's has french fries.' My tongue was bleeding from my biting it."

Safety first

"When you are pouring a bottle of wine tableside and the guest is insistent on moving or lifting the glass while you are pouring it.

“Letting their child run around. I once saw a child run right into a server carrying a tray of cappuccinos and a coffee pot. My son has the best restaurant manners because of this.”

$$$

"Patrons telling me things are expensive. This is a business. We would like to make a profit."

Splitting checks. It’s not a diner. Bring cash or get Venmo.”

You can be too good

We had guests who requested a bananas Foster. We did not have bananas in house. My general manager made me get bananas to make the dessert, even though we have so many choices and flavors. THEY CAME BACK AND ASKED FOR IT AGAIN.

Final words

"I wish everyone in general, from owners to patrons, would focus more on the core of our business: To have a great meal with friends or colleagues, and actually seek to enjoy the experience. … It's our business, not curing cancer here."

"I had a buser once say at a meeting, 'It's about them, not us.' I repeat this a lot. I also say, 'The customer is not always right, but they're always the customer.' "