Avoid ordering these items unless you want to seem like a jerk.
In a recent Reddit thread, workers candidly revealed the items that are difficult or confusing to prepare.
NOTE: Reddit sources are anonymous, and can't be independently verified by Business Insider. Some posts have been edited for clarity.
1. The "secret menu" at Starbucks.
Many Starbucks workers advised not to order off the "secret menu" - because it doesn't exist.
"If you want a snickerdoodle or Nutella Frappuccino, know the base drink and the modifications, and order that," says barista stac52. "If you just say the name, it's up to the barista to come up with what's in the drink, and it may not be what the last barista you ordered from put in there."
2. Chipotle quesarito.
This secret menu item is a huge pain for workers, writes Ssutuanjoe.
"When customers order them, every employee in the restaurant hates you," he writes.
3. McDonald's Mighty Wings.
"They are specialty items that are made by request, so we have to go to the freezer, set out a special area in the deep-fryer (The spiciness of the wings can mess with other foods) and they take FOREVER to make," writes kalib97. "If you're fine with waiting 7 extra minutes for your order, go ahead and buy those Mighty Wings."
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"If you order this sandwich, I hate you," writes cardinals1996. 
5. Chicken Littles at KFC.
"They are annoying to make as we have to put on gloves, and the lids on go-cups only fit on properly when the store is not busy, scientific fact," writes TristanaMyWaifu.
6. A bread bowl of broccoli cheddar soup at Panera Bread.
One worker writes that this is the most-ordered item at her restaurant.
"There isn't anything wrong, we just need a break from the mundane," writes bluesmoke95. "Order something new and extravagent. We get bored."
7. Late-night pizzas.
"One word of warning: do not show up 30 min before close, drunk, and order a double meat lover or ask me to 'hook you up' with double toppings," writes former Pizza Hut worker TheMightyFSM. "When dealing with more than 5 toppings the oven will not cook your pizza all the way through and I will laugh as you attempt to eat your pile of half-cooked dough."
7. Ridiculously modified food.
"Restaurants make food the way the chefs and general managers want to, not the way you do at home," writes diner employee cravecase. "Please trust that the people you are paying to cook your food, that they are doing it right."
8. Loaded-up Subway subs.
"When you order all of the veggies on your sandwich (especially flatbread) we want to murder you," writes Digital-Caffeine. "Stop asking us for extra extra extra spinach on top with three different sauces and then give us a dirty looks when your sandwich won't close."
9. McGangbangs at McDonald's.
The secret menu item is generally known to be a McChicken inside of a Double Cheeseburger.
The problem?
"It truly doesn't exist," writes canserpants. "So stop ordering them."
10. P'zolo at Pizza Hut.
"Subs take a lot of time and extra work, so workers don't put much effort into them, writes pottymouthgrl. "They mess up the flow when it's busy, and if we're really slammed, then we will probably be 'out of buns.'"
Pizza Hut