We all like to go out to eat on occasion. It's a nice thing to do! But I don't think people who haven't worked in restaurants understand just how gross is can get behind the scenes of even the fanciest joints. Someone asked the chefs of Reddit to share the red flags everyone should look out for when they go out to eat. Some of these are common sense; others, I've never even thought of before."Grade pending"You know how restaurants in some states have that big letter grade from the health inspector hanging up in their doorway. Well, ImSuperSick explains, "Grade Pending" doesn't mean they are waiting for a grade. "It means that they failed and are given a grace period to fix their wrongs." Better avoid those places.Sick waitstaffIf you can tell that the waitstaff is under the weather, maybe don't eat there, thick_andy says. If the servers are sick, there's a good chance you're going to get sick, too.Dirty dining roomBringMeTwo isn't a chef, but they used to work for a pest control service, and it was always the restaurants with dirty or gross dining rooms where they found trouble. If the front-facing area of the restaurant is nasty, imagine what's going on in the back. Ick.Grabbing glassesThis bad habit bothers arseniy1234555 and my mom alike. When waitstaff grab clean glasses at the top, a.k.a. the area that you'll be putting your mouth to, that's a big red flag. No one wants to taste someone else's fingers.Salt shakersIf the salt shakers are clogged or the tops are dirty, there's a good chance they haven't been cleaned in a very long time. And if they don't clean the salt shakers, imagine what else they don't clean. Thanks for this tip, faployst.Flour everywhereIhatetheplaceilive begs anyone with a serious gluten intolerance or wheat allergy not to eat at a scratch Italian restaurant. Even though these places might offer gluten-free options, there's flour everywhere, and there's simply nothing they can do about it.Soda machinesThis is an important one. StumbleKitty is a former health inspector who says if you're at a place with a self-serve soda machine, take a napkin to the inside of the nozzle for whichever soda is clear (Sprite/7-Up, etc.). If it comes out pink or orange, that's slime mold. Ew. If it's brown, it might be cola, but that still means that the nozzles aren't being cleaned properly.Overworked waitstaffIf the staff appears overworked, overwhelmed, or pissed off, maybe come back another time. If they're stretched thin, there's a lot of proper policy that could be flying out the window. Fiendlymcfiend knows what they're talking about.Dirty menusIt's so gross when you're handed a menu and there's gross, caked on food crusted to the edge. If a restaurant can't be bothered to clean their own menus, Nissir says, chances are there's a lot more that isn't getting the attention it deserves.Two different restaurantsGenerally, it's a good rule of thumb to avoid places that seem like they could be two (or more) different restaurants. Does a place serve pizza and sushi? Maybe you should skip it, says rukasu83. Of course, there are exceptions to this rule (sushi and burger joints are actually a thing), but make sure you do your research before you head to one of these places.Coffee machinesIf you're at a place with a visible coffee machine, "take a look at the steamer," writes fernanzgz. "If it's covered in white, that means they don't clean after frothing the milk." And it's very important to clean up old milk.Dry spotsI feel like at one point or another, we've all been to a restaurant where we've been handed a sad plate of food with dry spots in the corners. According to spoonedkittens, this means it has been left out for a long time, either in the cooked or raw state.Oyster originMaterialImportance implores us to please ask where the oysters and all seafood comes from before you order it at a restaurant. "If they don't know, you don't want them," they write.Weird smellRenewed_artist warns us that if there's a "funky smell that's even slightly (or stronger) urine-like," that probably means the restaurant has a rodent problem. And that's about as unsanitary as it gets.Too many unfed tablesOne chef, jeraco73, tells us that if the restaurant is busy but there are a lot of tables that don't have their food yet, "this usually means the kitchen is going down in flames." You don't want whatever cut-corners meal they're going to serve you.Fishy smellBellabane tells us, "If you actually smell fish at a sushi restaurant, it's in your and your insides' best interest to hightail it out of there." Fresh, sushi-grade fish shouldn't really have a fishy smell.Fried chicken no-noSlayinDaWabbits is a pest control professional who warns us that "95 percent of quick-serve fried chicken places are vomit-inducing. Particularly one based with an old guy as its mascot." Hm. That's reasoning enough for me to skip fried chicken places pretty much forever."No substitutions"Whenever I see "no substitutions" on a menu, I think the restaurant is just being stuck up and pretentious about its own food, but according to Edymnion, it sometimes means you're "getting frozen meals run through the microwave." I've never thought about that before, but it makes sense.Cross-contaminationIf you follow a very strict diet that you want to adhere to while you're eating out, says sitbuttadopo, don't eat out at most regular restaurants that offer only a few options that are vegan, gluten-free, etc. Cross-contamination happens way more often than we think. If you're militant about your vegan diet, for example, go to a completely vegan restaurant, not a restaurant with one or two vegan items.Hidden health scoreIf restaurants have a health score to be proud of, they will display it front and center. Gorytory tells us that if you can't readily see a restaurant's health inspection grade, there's probably a reason for that.