A high-end restaurant will only cut you off if you're an asshole
Upscale restaurants will accommodate even the most erm... enthusiastic guests as long as they're pleasant. But as soon as the attitude turns sour, service will happily put an end to the evening.
There's no point in lying to a hostess
They've got a bigger bullshit detector than your mom. They know if your friend is “parking” or just late. And your "reservation for three" that really means "reservation for six" is just as transparent. No use lying to them. Maybe try redirecting that energy into a tip.
Weird music means "leave"
The staff is ready to go home if the soundtrack takes a turn towards Metallica's later work or Justin Timberlake's early work. And if it's being played extra loud, that means you're really pushing the goodwill, no matter your feelings about the virtues of "Bye Bye Bye."
Cursing breaks down formality barriers
The interaction between server and guest can be uncomfortably rigid for everyone involved, but letting slip a four-letter word that doesn't start with the letter "C" is a nice way to deflate the tension and let the server know that they can talk to you like a peer rather than a servant.
Chefs don't use specials to get rid of old ingredients
Before service, most restaurants will cook up a large meal for the staff to share, which is where any about-to-turn produce or proteins will end up. Unless the restaurant is truly nefarious, there's no incentive for a chef to trick a diner with a special that they won't enjoy. In fact, it's more likely that the chef is testing out something he or she is truly proud of.
Sign up here for our daily Thrillist email, and get your fix of the best in food/drink/fun.
Dan Gentile is a staff writer at Thrillist. He didn't know half of these things. Follow him to apologizing for staying past closing at @Dannosphere.