RULES, RULES, RULES. Among the common complaints I hear from diners are that they feel victimized by restaurants' rules.

So do I sometimes. Arriving five minutes late for lunch at the Occidental Grill, I found my guest waiting in the entrance because the hostess wouldn't seat anybody, even if they had a reservation, until the whole party was there. That seems ungracious for a restaurant with $15 lunch entrees and $7.25 hamburgers.

After high school graduation time I heard complaints from young diners elsewhere who found they were given special graduation menus that had limited choices and smaller portions than other diners' menus. They were further insulted by tips being automatically tacked onto the bill.

That's a tough problem, since nobody wants to risk ruining prom night by arguing with the restaurateur, and few kids have the experience and confidence to stand up for their rights and refuse to be treated as second-class customers. Restaurants ought to realize -- and be reminded by the graduates or their parents afterwards -- that they are turning away future customers.

Holidays present other problems. On Father's Day, a group dining at Donatello who expected the fixed-price pre-theater dinner that had been promised in Friday's newspaper advertisements found that the special price is not available on holidays. So their dinner cost about 30 percent more than they had planned. The waiter explained that the special was not available on Father's Day, nor on Mother's Day, Valentine's Day or New Year's. But the advertisement had not specified that. The diners wrote to me and I called the restaurant to check.

"They are right, no question about it," said Donatello's manager Joseph Soares. "It was an honest mistake (of the waiter's)."

And he was upset that they had taken their complaint to the newspaper. But since the waiter gave them no satisfaction, the diners were powerless to exert their rights on the spot. So the customers were the ones to pay for that honest mistake.

Then there is Sunday brunch, when diners expecting to order a` la carte breakfast -- or even lunch -- may find they are stuck with a buffet. Any diner reserving a table for a daytime meal on Sunday should anticipate the problem and ask a few questions beforehand.

Finally, there are the tea and coffee complaints. Why does a restaurant charge for a second cup of tea but not a second cup of coffee? Why is the charge for hot water and lemon the same as for coffee or tea? When refills of plain coffee are free, why does a restaurant charge for refilling a cup of cappuccino or cafe au lait with plain coffee?

The answer is: because restaurants can charge what they want, and some are willing to lose the goodwill of a customer over a cup of boiling water.

A reader wrote me recently about an overpriced martini at the Willard Hotel's Round Robin Lounge. Her complaint may have been warranted, but not for the reason she thought. She thought that the surcharge of 50 cents on her martini was for the vermouth, when actually it was for the lack of ice. The way it works is that a martini (or any bar-brand drink) at the Willard's bar costs $4.75 on the rocks. But if you order it without ice -- as in a classic martini -- it results in a larger portion, two ounces rather than 1 1/2, and the bar charges for the extra gin.

I can't quite figure the logic of this. If a half ounce of gin costs 50 cents, then the 1 1/2-ounce drink should cost $1.50. Admittedly the glass, preparation, cleanup and table occupancy are worth something, but $3.25 extra?

That's not the only surprise I heard from the Willard. Dining room manager Jim Hutton tells me that the most popular cocktail by far these days is premium vodka. Absolut is the number-one brand, he's observed, and people are drinking it straight. It has severely cut into sales of champagne by the glass, and white wine has apparently gone out with the '80s.

Phyllis C. Richman's restaurant reviews appear Sundays in The Washington Post Magazine.