Here's what they said:
1. "Number one evaluation effect for me is smell. If it’s a sour smell or disinfectant smell — red flag."
2. "Random, but if there's a fish tank, take a look at it. If it's clean, you can bet the kitchen is too."
3. "Dirty bathrooms and dirty floors equal dirty kitchen."
4. "A huge menu is a sign that food is either frozen, precooked, and reheated — or ingredients are not very fresh."
5. "Ex-chef here, but weirdly, the setting. I've found if a restaurant puts effort into the ambiance, it's normally an extension of their food. Not always, but it has been a pretty solid rule."
—deleted
6. "Where's the manager and what are they doing? Do they look exhausted or are they upbeat, helpful, and engaging with their staff? Good managers tend to attract good staff which in turn leads to a good business. Bad management does exactly the opposite."
7. "Carpet is a red flag — it's quieter and doesn't get slick, but it is one of the most disgusting things I've ever seen in restaurants. Vacuuming only goes so far."
8. "The bread. It has to be good bread. If they can't get the bread right, they don't know anything. No chef in their right mind half-asses the bread."
9. "Look at the wait staff's name tags. People usually keep the same name tags the entire time they work there. There should be a little bit of wear and tear on them. If everyone has brand new name tags, that means they're all new, and service is going to be slow and bad. It also shows that the restaurant isn't good at staff retention and should make you question the quality of what you're eating."
10. "If you can smell the seafood when you walk in, then it's not fresh. Fresh seafood doesn't have that scent we usually associate with it — it doesn't get that until it's old."
https://www.buzzfeed.com/ryanschocket2/chefs-share-restaurant-red-flags?origin=tuh