A thread ask AskReddit poses the question: "Chefs of Reddit, what are some 'red flags' people should look out for when they go out to eat?" There's plenty to digest in the answers. Buzzfeed lists some of the more notable.
4. "Specials are just leftovers — they're things that we'd rather sell than throw out."
5. "Ask where your seafood comes from. If they don’t know, you don’t want it."
7. "Watch for 'No Substitutions.' If the place makes its own food, they can sub virtually anything for anything else. While they may try to play it up as 'Our food is perfect and we refuse to change it on moral grounds,' it's almost always a sign of 'This was made two months ago and all we do is reheat it.'"
You can read the entire thread here, or check out the short version in 15 Restaurant "Red Flags" You Should Look For When You Go Out To Eat at Buzzfeed.