McDonald's jobs are abundant.
About 375,000 people work at the fast-food chain, according to a 2016 McDonald's filing. But if you include franchise employees, as Forbes did in 2015, the number jumps to 1.9 million, making McDonald's one of the largest employers in the world.
Whether they work for franchise locations or corporate stores, McDonald's employees gain a keen insight into the inner workings of the fast-food giant.
McDonald's employees can tell you all about the most annoying customer requests and the consequences of working around french fries all day.
Here are a few things only McDonald's employees know.
People Can Get Pretty Invested in Their Food
"I was amazed at how furious people could get over food," a person who says they worked at McDonald's wrote on Reddit. "I was a swing manager for a while, and one time I took a call from an angry guy ... Seems that even though he asked for no mustard on his burgers, he got mustard."
The Reddit user said the man claimed to have a spreadsheet on which he recorded every time a McDonald's employee made a mistake with his food. He yelled and kept demanding to speak to the store owner.
The Reddit user said the owner ended up taking a call from the man and promptly hung up after telling him to find "somewhere else to eat in the future."
There's a Trick to Getting a Fresh Egg on Your Breakfast Sandwich
Mackenzie Shelton, whose Quora bio says she's a McDonald's employee, offered a hack for getting a fresh-from-the-carton egg on your breakfast sandwich.
Request a "round egg," she said. "It's the best egg we have (and definitely real!)."
The website Serious Eats confirmed that the request could swap out "your folded egg patty with a real egg, free of charge."
Chuck Chan, who says he worked at McDonald's, wrote on Quora that you'd get the same type of egg used in McMuffins.
Employees Sometimes Get Some Unusual Requests
Sometimes customers come up with some rather unusual requests for McDonald's employees to tackle.
A McDLT is a discontinued McDonald's sandwich that consisted of a cheeseburger split in two and placed on different sides of a specialized container. One half had a bun with a patty and cheese (the hot side), while the other had a bun with vegetables and sauce (the cold side).
"For some odd reason, this seemed to be the funniest thing the girl behind the counter had ever heard and she started laughing," Bowerbank wrote. "And she couldn't stop. The assistant manager had to step in, apologize, and put in the order for her."
Ganesh Satyanarayana said on Quora that while he was working the closing shift at a McDonald's in the UK, he encountered a customer he described as "visibly pregnant."
"She quietly asks me: 'Are you still open? Because I'm craving a sandwich and none of the other McDonald's were open,'" Satyanarayana wrote. "My heart immediately melted and I let them in and told them that it would take a while as I had already finished cleaning the oil vats and the grill. She said: 'Oh, I don't want any meat on my sandwich, I just want pickles on a toasted bun.' I swear to God, I thought she was joking."
And not all of the strange requests involve food. Arthur Adams, who says he worked at a McDonald's in the 1980s, said on Quora that customers would ask him to tell a joke or sell his McDonald's hat.
Custom Orders Are Sometimes a Pain
In a Reddit "Ask Me Anything" thread last year, a McDonald's employee said custom orders could be a pain to make.
"We label it as 'special request,'" they wrote, so the employees filling the order "have to literally stop working just to come over and ask what the special request is."
They added that requesting "something fresh" could also count as a custom order, as well as requests that ketchup be squirted between burger patties or for a specific placement of the cheese in a sandwich.
The employee gave the examples of a sandwich that substitutes the bun for lettuce or getting just one pancake instead of the standard three.
"It gets weirdly specific," the employee wrote.
McDonald's Employees in the UK May Be More Attentive at Certain Times — and Customers Can Use This to Their Advantage
In the UK, McDonald's employees might be especially attentive at certain times of the day.
Kamran Adnan, who said he worked for a year at McDonald's locations in London, said on Quora that 12 p.m. to 2 p.m. and 5 p.m. to 7 p.m. were called "gapbuster times," or times when mystery shoppers who get paid to rate their experience may visit a McDonald's restaurant.
"It is easy to spot a gapbuster because they always ask for a receipt so they can get their food costs reimbursed by the company employing them," Adnan wrote.
He continued: "If you ask for a receipt in that time, everyone will be immediately alert that you could be a potential gapbuster, and they'll make sure to serve you the freshest burger and fries and give you priority over everyone else."
There Are Several Types of Managers
Managers at McDonald's can perform a variety of tasks, depending on their level.
A Reddit user who said they had worked at McDonald's for five years broke down the chain of command at the store:
• The owner or operator is at the helm.
• The restaurant manager oversees the whole store and things like "procedures, scheduling, admin, HR."
• At large McDonald's locations, secondary managers or salary managers take on some of the responsibilities of the restaurant manager.
• Swing managers and shift managers work on the floor with the rest of the employees.
Some Employees Use the Kitchen to Make Their Own Meals
Some employees chow on Big Macs during their lunch break.
Jasmine Nathaniel, who says she works at McDonald's, said on Quora that others opted for a bit more variety.
"Sometimes we got creative in the kitchen and would whip up our own meals," she wrote. "I have made many quesadillas and grilled cheese bacon sandwiches in my time."
Some Customers Can Be Pretty Condescending
It's no secret that some people make a point of looking down on fast-food workers.
A McDonald's employee named Mike Waite addressed some of this condescension in a viral Facebook post in 2016.
"YES I work at McDonald's and do it nearly 50 hours a week," Waite wrote. "Why? Not because I have no aspiration, motivation or intelligence ... but for the opposite ... because in a few months' time, like a great number of people I work with, I will be going back into higher education."
He said he aspired to be like his colleagues at the chain.
"In the past I have known and worked with very rich folks in very high-end jobs, and a few of them could never match the resilience and work ethic of some of the current lads/lassies," he wrote.
A Reddit user who said they were once a part-time McDonald's employee described one uncomfortable situation where she overheard a customer speaking with her children.
"I LITERALLY hear the mother say to her kids, 'Remember, if you don't do well in school, THAT'S how you'll turn out,'" the Reddit user wrote. "It took all my effort not to turn and berate her for her ignorance. Not only are half the employees I work with in full-time education like me ... but the other half were all upstanding, good individuals (in their own ways) who I respected as much as they respected me."
Asking for Fries With No Salt Is a Good Way to Annoy Employees, and You May Be Better Off Just Asking for Fresh Fries
A popular myth circulating on the internet is that you can snag fresh fries by asking for fries with no salt.
"Buddy, there's a 90% chance that you read some 'life hack' on Reddit, or Imgur, or what have you, that says to get fresh fries just ask for no salt," a person who says they were a McDonald's employee wrote on Reddit. "Do you realize you can just ASK us for 'fresh,' and we're more likely to give them to you, right?"
Another Reddit user responded: "I understand that some people genuinely have to limit their salt intake as much as possible (McDonald's isn't really the best place to practice that sort of diet, but hey, not my life) but for me, at least, it's easy to tell who genuinely needs it salt free and who's just trying to get the freshest fries they can."
Chan said on Quora that while it's true that asking for fries with no salt will get you fresh fries, preparing the order is a nuisance.
"The fry person will need to wipe down the station, the fry scoop, and clear the area for the new batch to keep salt from contaminating the new batch," Chan said. "The fry person might not even fill up your container as full due to this fuss. And if any fries fall out of the bag/container, they won't put more in because the rest of the fries may have already been salted."
He recommended instead just asking for fresh fries.
Ask for the Budget Version of the Big Mac
Shelton said on Quora that people trying to cut costs but "craving a Big Mac" could ask for a McDouble "dressed like a Big Mac — hold the ketchup and mustard, add lettuce and Mac sauce."
"You'll save a few bucks and I've heard they taste great too," she wrote.
It's Hard To Get Rid of the Smell of French Fries
Have you ever grabbed a McDonald's meal at the drive-thru, then noticed that your car smells like french fries for days?
McDonald's employees say they have to live with that every day.
A person who said they used to work the grill at McDonald's wrote on Reddit that showering the second you get home is key.
"Don't expose your regular clothes to your work clothes," they said. "Wash separately."
Another Reddit user who said they were a cashier, cook, and drive-thru worker at the chain wrote: "I smell like french fries until I shower."
One person asked the McDonald's subreddit for help.
"I am employed at a McDonald's, and since I am frequently on the grill and fried products, my uniform always smells like grease, and I can't get it out," they wrote. "The shirt is 100% polyester, so I think that may be why it still does, so does anyone know how to get out the smell?"
"Just don't worry about it," another person who said they were a McDonald's employee responded. "It's your uniform. It's bound to smell that way. It's not like you're going to wear it to a party or something."
One former McDonald's employee who reached out to Business Insider suggested dousing your laundry in lemon juice to diminish the odor.
This article originally appeared on BusinessInsider.com.