Telling them the "recipe" to make an item

It can be tempting to tell an employee how to make something, especially if you've worked at that restaurant before or if the employee seems new or uncertain. You know the recipe for the Chicken Club BLT or all the ingredients for the salad, so you'll just save them the time of having to look it up, right? Resist that urge.

"I work at McDonald's, and it turns out a ton of other people have worked at McDonald's or know someone who has, so there are a lot of people who want to tell me how to do something, like how to make a certain sandwich," says George H. "But I usually already know, and also sometimes the instructions have changed or we no longer offer that particular item." Trying to do a worker's job for them comes across as patronizing and can also imply that you think they're dumb.

Do this instead: Be patient while the worker makes your order, and don't hover over the counter. If your order ends up incorrect, simply ask them to fix it or replace it.

Telling them to "just do" something

Some things fast-food workers have to do may look inefficient or frustrating (and sometimes they really are!). It may seem kind to give them "permission" to do it in a faster or easier way. "I recently had a customer tell me to 'just do' this ingredient substitution instead of waiting for more to come out," says Jo. "But it had already been put into the system the first way, and it would have changed how much it cost, so I would have had to make an adjustment, which probably would take longer than just waiting for more chicken." Then the customer told Jo to just charge him the first price even if it was a little higher, which she says she can't do either because it messes up the inventory and order numbers.

Do this instead: You're not their boss, so you really can't give them permission to subvert the rules, even if they wish you could. Allow the worker to do their job the way they've been taught, even if it feels inefficient.

Warning them about mistakes they might make

Perhaps the last time you went to this particular chain, the worker got your order wrong or forgot the straws or made some other mistake. You may think it's helpful to tell the fast-food worker who is currently helping you about the past issue so you don't have to bother them to "fix" the problem if it happens again. But you have to remember that while each franchise in a chain looks alike, each employee is different, and unless you're dealing with the same person, they are unlikely to make the same mistake. Sharing problems with past orders can just come across as complaining.

"I had a lady order a salad and then tell me, like, five things to 'watch out for' when making it because whoever did it before did it wrong. But I don't even think she was at our location when she made that order," says Calvin L., who works at Chick-Fil-A. "She said she was just trying to save time by warning me in advance so I didn't make those same mistakes, which honestly felt kind of insulting."

Do this instead: Be clear about your order, and allow the workers to make it to your specifications. If something is wrong, ask them to fix it.

Asking your server at a sit-down restaurant what they recommend you order is a perfectly polite question, not to mention a great way to get a delicious dish. But it's a different story at fast-food restaurants, Caleb says. First, the menu items are generally simple, well known and don't change, so the food should basically be the same every time. Second, asking the person at the register what they recommend takes extra time and holds up the line.

"I think they think I'll be flattered that they want my opinion, but I don't know them at all, and I don't want to play 20 questions to figure out what they like," Caleb explains. "Also, I never know what to say when people ask me what's good here."

Do this instead: If you're undecided about your order, stand out of the line until you know what you want. Feel free to ask questions about ingredients or flavors, but don't ask the employee for their personal opinion about what you should order.

Ordering "the usual"

Many regular customers frequent a particular fast-food restaurant because they have a favorite meal they like to eat. And if you go in regularly, the staff will likely begin to recognize you and may even remember what you like. So simply ordering "the usual" saves everyone time, right? This only works if they do remember your order, and it may make them feel bad or annoyed if they don't—after all, they serve hundreds of people every day.

"I'm pretty face-blind, so even when people come in every day, I don't always recognize them," Caleb says. "Then they'll be like, 'Oh, hey—I'm in here every day. Remember me?' And then I have to say no."

Do this instead: If the staff member asks you if you want your "usual," consider it great service! But don't expect them to remember it.