Waiters and waitresses attempt to establish an intimacy with customers, in order to increase tips. How? Touching you on the shoulder or grazing your hand establishes a desire on your part to reciprocate, says Mike Lynn, associate professor at the School of Hotel Administration at Cornell University.

“Lots of people counter, ‘I don’t like the idea of being touched: This doesn’t work with me!’ Well, they’re wrong,” says Lynn, who studies tipping behaviors. Squatting down to be at your eye level, scrawling a “thank you” and a smiley face on the check, remembering your name (from your reservation) and giving you an “extra” treat, such as an after-dinner candy or mint, to gain better social rapport, also ups the outflow from your wallet. What about tipping just for solid, professional service? “Good service does improve tips, but surprisingly not by much,” says Lynn — at most by about four percent.

2. The Tip May Not Go To Your Server

Your waiter or waitress “may be required to give a cut of the tip to the bartender, busboy, food runner and other people who participate in your service,” explains Lynn. In that case, the $10 you gave your waiter won’t directly go into his pocket. Some restaurants have a “tip pool,” into which all servers pool their tips and then divide them at the end of the day or week. If your “tip” is really an obligatory “service charge” — a popular way of subsidizing labor costs in Miami, though less so elsewhere — “the restaurant is free to use that money any way it sees fit,” notes Lynn.

3. Your Wallet Is Targeted

There’s a reason that Chinese restaurants and fast-food joints have succulent images of their fare on menu boards and that chain restaurants display table cards featuring photographs of desserts and drinks. Come-hither, glistening images of food — called “gastro porn” in the food industry — induce people to buy more.

Visual suggestions are abetted by verbal ones: “Would you like sparkling water or mineral water?” (Tap water isn’t even suggested!) “Our desserts are great tonight.” (Assumes that you want dessert.) “Would you like fries with that?” (Oh, yes, fries! Hadn’t planned on that, but why not?) “It’s called up-selling,” explains Stephani Robson, a senior lecturer at the School of Hotel Administration at Cornell University.

Drinks and refills are pushed the most, because they make the most money for the restaurant. Wine is usually marked up 100 to 200 percent, beer even more and “soda is almost pure profit; the syrup and carbonated water cost the restaurant just pennies per serving,” points out Robson. Even the credit card logos behind the register and on the check tray prompt a plumper payout! “Americans are conditioned to spend more money in the presence of credit card stimuli,” says Lynn.

4. The Seafood Isn't Jumping

The fillet of sole, salmon or swordfish you order was probably frozen. But that’s not necessarily a bad thing if it was “flash frozen” on the boat immediately after being caught, says Kevin Moll, CEO and president of National Food Service Advisors. In many instances, he explains, flash frozen fish tastes (and smells) better than travel-weary “fresh” fish six or seven days old. Another fishy trick? Restaurants sometimes substitute cheaper kinds of fish for more expensive species listed on the menu, hoping that you don’t notice the difference. But this is unethical, says Moll.

So speak up and be a smart consumer, urges Robson. Ask the server or manager: “Where does the crab come from? What kind of crab is it?” If you let restaurant personnel know in a friendly way what you really care about — “I’m picky about my fish; would you order it tonight?” — you are more likely to be satisfied.

5. Restaurants Overbook — Just Like Airlines Do

Fifteen to twenty percent of people with a reservation don’t show, so restaurants overbook. When the restaurant miscalculates the frequency of flakiness, you may wait a long time. What to do? When you make the reservation, “say that the evening is a special occasion,” advises Moll. Then call back two or three days before the date to confirm. Show up early as well “and never expect immediate seating. A 15-minute wait is normal,” he explains. Also, don’t leave a reservation request on the restaurant’s answering machine. “Talk to a person. Write down his or her name,” says Moll. That name will come in handy if you arrive only to be told that you have no reservation.

6. Menus Are Rigged; "Specials" Are Sneaky

Research shows that people are most likely to glance at the upper right portion of the menu first, then to the upper left corner and then to the bottom right corner. Restaurateurs strategically nestle their highest profit (though not necessarily their most expensive) items in these three places. But selecting from these spots can be a good bet. Those areas usually have the freshest items because they are popular and have high turnover. The owner may go the distance to make these high-profile dishes particularly satisfying.

Finally, ask the price of the “specials” that are verbally recited by your server. These specials often cost much more than written, regular menu items and are pushed by staff to drive up your bill. In fact, any deviation from the printed menu — even sharing an entrée or getting a sauce on the side — may have a surcharge. Don’t be embarrassed to ask: “Is there a fee for that?”